text: //     Backbone.js 0.9.2
  
  //     (c) 2010-2012 Jeremy Ashkenas, DocumentCloud Inc.
  //     Backbone may be freely distributed under the MIT license.
  //     For all details and documentation:
  //     http://backbonejs.org
  
  (function(root, factory) {
    // Set up Backbone appropriately for the environment.
    if (typeof exports !== 'undefined') {
      // Node/CommonJS, no need for jQuery in that case.
      factory(root, exports, require('underscore'));
    } else if (typeof define === 'function' && define.amd) {
      // AMD
      define(['underscore', 'jquery', 'exports'], function(_, $, exports) {
        // Export global even in AMD case in case this script is loaded with
        // others that may still expect a global Backbone.
        root.Backbone = factory(root, exports, _, $);
      });
    } else {
      // Browser globals
      root.Backbone = factory(root, {}, root._, (root.jQuery || root.Zepto || root.ender));
    }
  }(this, function(root, Backbone, _, $) {
  
    // Initial Setup
    // -------------
  
    // Save the previous value of the `Backbone` variable, so that it can be
    // restored later on, if `noConflict` is used.
    var previousBackbone = root.Backbone;
  
    // Create a local reference to array methods.
    var ArrayProto = Array.prototype;
    var push = ArrayProto.push;
    var slice = ArrayProto.slice;
    var splice = ArrayProto.splice;
  
    // Current version of the library. Keep in sync with `package.json`.
    Backbone.VERSION = '0.9.2';
  
    // For Backbone's purposes, jQuery, Zepto, or Ender owns the `$` variable.
    Backbone.$ = $;
  
    // Runs Backbone.js in *noConflict* mode, returning the `Backbone` variable
    // to its previous owner. Returns a reference to this Backbone object.
    Backbone.noConflict = function() {
      root.Backbone = previousBackbone;
      return this;
    };
  
    // Turn on `emulateHTTP` to support legacy HTTP servers. Setting this option
    // will fake `"PUT"` and `"DELETE"` requests via the `_method` parameter and
    // set a `X-Http-Method-Override` header.
    Backbone.emulateHTTP = false;
  
    // Turn on `emulateJSON` to support legacy servers that can't deal with direct
    // `application/json` requests ... will encode the body as
    // `application/x-www-form-urlencoded` instead and will send the model in a
    // form param named `model`.
    Backbone.emulateJSON = false;
  
    // Backbone.Events
    // ---------------
  
    // Regular expression used to split event strings
    var eventSplitter = /\s+/;
  
    // A module that can be mixed in to *any object* in order to provide it with
    // custom events. You may bind with `on` or remove with `off` callback functions
    // to an event; `trigger`-ing an event fires all callbacks in succession.
    //
    //     var object = {};
    //     _.extend(object, Backbone.Events);
    //     object.on('expand', function(){ alert('expanded'); });
    //     object.trigger('expand');
    //
    var Events = Backbone.Events = {
  
      // Bind one or more space separated events, `events`, to a `callback`
      // function. Passing `"all"` will bind the callback to all events fired.
      on: function(events, callback, context) {
        var calls, event, list;
        if (!callback) return this;
  
        events = events.split(eventSplitter);
        calls = this._callbacks || (this._callbacks = {});
  
        while (event = events.shift()) {
          list = calls[event] || (calls[event] = []);
          list.push(callback, context);
        }
  
        return this;
      },
  
      // Remove one or many callbacks. If `context` is null, removes all callbacks
      // with that function. If `callback` is null, removes all callbacks for the
      // event. If `events` is null, removes all bound callbacks for all events.
      off: function(events, callback, context) {
        var event, calls, list, i;
  
        // No events, or removing *all* events.
        if (!(calls = this._callbacks)) return this;
        if (!(events || callback || context)) {
          delete this._callbacks;
          return this;
        }
  
        events = events ? events.split(eventSplitter) : _.keys(calls);
  
        // Loop through the callback list, splicing where appropriate.
        while (event = events.shift()) {
          if (!(list = calls[event]) || !(callback || context)) {
            delete calls[event];
            continue;
          }
  
          for (i = list.length - 2; i >= 0; i -= 2) {
            if (!(callback && list[i] !== callback || context && list[i + 1] !== context)) {
              list.splice(i, 2);
            }
          }
        }
  
        return this;
      },
  
      // Trigger one or many events, firing all bound callbacks. Callbacks are
      // passed the same arguments as `trigger` is, apart from the event name
      // (unless you're listening on `"all"`, which will cause your callback to
      // receive the true name of the event as the first argument).
      trigger: function(events) {
        var event, calls, list, i, length, args, all, rest;
        if (!(calls = this._callbacks)) return this;
  
        rest = [];
        events = events.split(eventSplitter);
  
        // Fill up `rest` with the callback arguments.  Since we're only copying
        // the tail of `arguments`, a loop is much faster than Array#slice.
        for (i = 1, length = arguments.length; i < length; i++) {
          rest[i - 1] = arguments[i];
        }
  
        // For each event, walk through the list of callbacks twice, first to
        // trigger the event, then to trigger any `"all"` callbacks.
        while (event = events.shift()) {
          // Copy callback lists to prevent modification.
          if (all = calls.all) all = all.slice();
          if (list = calls[event]) list = list.slice();
  
          // Execute event callbacks.
          if (list) {
            for (i = 0, length = list.length; i < length; i += 2) {
              list[i].apply(list[i + 1] || this, rest);
            }
          }
  
          // Execute "all" callbacks.
          if (all) {
            args = [event].concat(rest);
            for (i = 0, length = all.length; i < length; i += 2) {
              all[i].apply(all[i + 1] || this, args);
            }
          }
        }
  
        return this;
      }
  
    };
  
    // Aliases for backwards compatibility.
    Events.bind   = Events.on;
    Events.unbind = Events.off;
  
    // Backbone.Model
    // --------------
  
    // Create a new model, with defined attributes. A client id (`cid`)
    // is automatically generated and assigned for you.
    var Model = Backbone.Model = function(attributes, options) {
      var defaults;
      var attrs = attributes || {};
      if (options && options.collection) this.collection = options.collection;
      if (options && options.parse) attrs = this.parse(attrs);
      if (defaults = _.result(this, 'defaults')) {
        attrs = _.extend({}, defaults, attrs);
      }
      this.attributes = {};
      this._escapedAttributes = {};
      this.cid = _.uniqueId('c');
      this.changed = {};
      this._changes = {};
      this._pending = {};
      this.set(attrs, {silent: true});
      // Reset change tracking.
      this.changed = {};
      this._changes = {};
      this._pending = {};
      this._previousAttributes = _.clone(this.attributes);
      this.initialize.apply(this, arguments);
    };
  
    // Attach all inheritable methods to the Model prototype.
    _.extend(Model.prototype, Events, {
  
      // A hash of attributes whose current and previous value differ.
      changed: null,
  
      // A hash of attributes that have changed since the last time `change`
      // was called.
      _changes: null,
  
      // A hash of attributes that have changed since the last `change` event
      // began.
      _pending: null,
  
      // A hash of attributes with the current model state to determine if
      // a `change` should be recorded within a nested `change` block.
      _changing : null,
  
      // The default name for the JSON `id` attribute is `"id"`. MongoDB and
      // CouchDB users may want to set this to `"_id"`.
      idAttribute: 'id',
  
      // Initialize is an empty function by default. Override it with your own
      // initialization logic.
      initialize: function(){},
  
      // Return a copy of the model's `attributes` object.
      toJSON: function(options) {
        return _.clone(this.attributes);
      },
  
      // Proxy `Backbone.sync` by default.
      sync: function() {
        return Backbone.sync.apply(this, arguments);
      },
  
      // Get the value of an attribute.
      get: function(attr) {
        return this.attributes[attr];
      },
  
      // Get the HTML-escaped value of an attribute.
      escape: function(attr) {
        var html;
        if (html = this._escapedAttributes[attr]) return html;
        var val = this.get(attr);
        return this._escapedAttributes[attr] = _.escape(val == null ? '' : '' + val);
      },
  
      // Returns `true` if the attribute contains a value that is not null
      // or undefined.
      has: function(attr) {
        return this.get(attr) != null;
      },
  
      // Set a hash of model attributes on the object, firing `"change"` unless
      // you choose to silence it.
      set: function(key, val, options) {
        var attr, attrs;
        if (key == null) return this;
  
        // Handle both `"key", value` and `{key: value}` -style arguments.
        if (_.isObject(key)) {
          attrs = key;
          options = val;
        } else {
          (attrs = {})[key] = val;
        }
  
        // Extract attributes and options.
        var silent = options && options.silent;
        var unset = options && options.unset;
        if (attrs instanceof Model) attrs = attrs.attributes;
        if (unset) for (attr in attrs) attrs[attr] = void 0;
  
        // Run validation.
        if (!this._validate(attrs, options)) return false;
  
        // Check for changes of `id`.
        if (this.idAttribute in attrs) this.id = attrs[this.idAttribute];
  
        var changing = this._changing;
        var now = this.attributes;
        var escaped = this._escapedAttributes;
        var prev = this._previousAttributes || {};
  
        // For each `set` attribute...
        for (attr in attrs) {
          val = attrs[attr];
  
          // If the new and current value differ, record the change.
          if (!_.isEqual(now[attr], val) || (unset && _.has(now, attr))) {
            delete escaped[attr];
            this._changes[attr] = true;
          }
  
          // Update or delete the current value.
          unset ? delete now[attr] : now[attr] = val;
  
          // If the new and previous value differ, record the change.  If not,
          // then remove changes for this attribute.
          if (!_.isEqual(prev[attr], val) || (_.has(now, attr) !== _.has(prev, attr))) {
            this.changed[attr] = val;
            if (!silent) this._pending[attr] = true;
          } else {
            delete this.changed[attr];
            delete this._pending[attr];
            if (!changing) delete this._changes[attr];
          }
  
          if (changing && _.isEqual(now[attr], changing[attr])) delete this._changes[attr];
        }
  
        // Fire the `"change"` events.
        if (!silent) this.change(options);
        return this;
      },
  
      // Remove an attribute from the model, firing `"change"` unless you choose
      // to silence it. `unset` is a noop if the attribute doesn't exist.
      unset: function(attr, options) {
        options = _.extend({}, options, {unset: true});
        return this.set(attr, null, options);
      },
  
      // Clear all attributes on the model, firing `"change"` unless you choose
      // to silence it.
      clear: function(options) {
        options = _.extend({}, options, {unset: true});
        return this.set(_.clone(this.attributes), options);
      },
  
      // Fetch the model from the server. If the server's representation of the
      // model differs from its current attributes, they will be overriden,
      // triggering a `"change"` event.
      fetch: function(options) {
        options = options ? _.clone(options) : {};
        var model = this;
        var success = options.success;
        options.success = function(resp, status, xhr) {
          if (!model.set(model.parse(resp, xhr), options)) return false;
          if (success) success(model, resp, options);
        };
        return this.sync('read', this, options);
      },
  
      // Set a hash of model attributes, and sync the model to the server.
      // If the server returns an attributes hash that differs, the model's
      // state will be `set` again.
      save: function(key, val, options) {
        var attrs, current, done;
  
        // Handle both `"key", value` and `{key: value}` -style arguments.
        if (key == null || _.isObject(key)) {
          attrs = key;
          options = val;
        } else if (key != null) {
          (attrs = {})[key] = val;
        }
        options = options ? _.clone(options) : {};
  
        // If we're "wait"-ing to set changed attributes, validate early.
        if (options.wait) {
          if (!this._validate(attrs, options)) return false;
          current = _.clone(this.attributes);
        }
  
        // Regular saves `set` attributes before persisting to the server.
        var silentOptions = _.extend({}, options, {silent: true});
        if (attrs && !this.set(attrs, options.wait ? silentOptions : options)) {
          return false;
        }
  
        // Do not persist invalid models.
        if (!attrs && !this._validate(null, options)) return false;
  
        // After a successful server-side save, the client is (optionally)
        // updated with the server-side state.
        var model = this;
        var success = options.success;
        options.success = function(resp, status, xhr) {
          done = true;
          var serverAttrs = model.parse(resp, xhr);
          if (options.wait) serverAttrs = _.extend(attrs || {}, serverAttrs);
          if (!model.set(serverAttrs, options)) return false;
          if (success) success(model, resp, options);
        };
  
        // Finish configuring and sending the Ajax request.
        var xhr = this.sync(this.isNew() ? 'create' : 'update', this, options);
  
        // When using `wait`, reset attributes to original values unless
        // `success` has been called already.
        if (!done && options.wait) {
          this.clear(silentOptions);
          this.set(current, silentOptions);
        }
  
        return xhr;
      },
  
      // Destroy this model on the server if it was already persisted.
      // Optimistically removes the model from its collection, if it has one.
      // If `wait: true` is passed, waits for the server to respond before removal.
      destroy: function(options) {
        options = options ? _.clone(options) : {};
        var model = this;
        var success = options.success;
  
        var destroy = function() {
          model.trigger('destroy', model, model.collection, options);
        };
  
        options.success = function(resp) {
          if (options.wait || model.isNew()) destroy();
          if (success) success(model, resp, options);
        };
  
        if (this.isNew()) {
          options.success();
          return false;
        }
  
        var xhr = this.sync('delete', this, options);
        if (!options.wait) destroy();
        return xhr;
      },
  
      // Default URL for the model's representation on the server -- if you're
      // using Backbone's restful methods, override this to change the endpoint
      // that will be called.
      url: function() {
        var base = _.result(this, 'urlRoot') || _.result(this.collection, 'url') || urlError();
        if (this.isNew()) return base;
        return base + (base.charAt(base.length - 1) === '/' ? '' : '/') + encodeURIComponent(this.id);
      },
  
      // **parse** converts a response into the hash of attributes to be `set` on
      // the model. The default implementation is just to pass the response along.
      parse: function(resp, xhr) {
        return resp;
      },
  
      // Create a new model with identical attributes to this one.
      clone: function() {
        return new this.constructor(this.attributes);
      },
  
      // A model is new if it has never been saved to the server, and lacks an id.
      isNew: function() {
        return this.id == null;
      },
  
      // Call this method to manually fire a `"change"` event for this model and
      // a `"change:attribute"` event for each changed attribute.
      // Calling this will cause all objects observing the model to update.
      change: function(options) {
        var changing = this._changing;
        var current = this._changing = {};
  
        // Silent changes become pending changes.
        for (var attr in this._changes) this._pending[attr] = true;
  
        // Trigger 'change:attr' for any new or silent changes.
        var changes = this._changes;
        this._changes = {};
  
        // Set the correct state for this._changing values
        var triggers = [];
        for (var attr in changes) {
          current[attr] = this.get(attr);
          triggers.push(attr);
        }
  
        for (var i=0, l=triggers.length; i < l; i++) {
          this.trigger('change:' + triggers[i], this, current[triggers[i]], options);
        }
        if (changing) return this;
  
        // Continue firing `"change"` events while there are pending changes.
        while (!_.isEmpty(this._pending)) {
          this._pending = {};
          this.trigger('change', this, options);
          // Pending and silent changes still remain.
          for (var attr in this.changed) {
            if (this._pending[attr] || this._changes[attr]) continue;
            delete this.changed[attr];
          }
          this._previousAttributes = _.clone(this.attributes);
        }
  
        this._changing = null;
        return this;
      },
  
      // Determine if the model has changed since the last `"change"` event.
      // If you specify an attribute name, determine if that attribute has changed.
      hasChanged: function(attr) {
        if (attr == null) return !_.isEmpty(this.changed);
        return _.has(this.changed, attr);
      },
  
      // Return an object containing all the attributes that have changed, or
      // false if there are no changed attributes. Useful for determining what
      // parts of a view need to be updated and/or what attributes need to be
      // persisted to the server. Unset attributes will be set to undefined.
      // You can also pass an attributes object to diff against the model,
      // determining if there *would be* a change.
      changedAttributes: function(diff) {
        if (!diff) return this.hasChanged() ? _.clone(this.changed) : false;
        var val, changed = false, old = this._previousAttributes;
        for (var attr in diff) {
          if (_.isEqual(old[attr], (val = diff[attr]))) continue;
          (changed || (changed = {}))[attr] = val;
        }
        return changed;
      },
  
      // Get the previous value of an attribute, recorded at the time the last
      // `"change"` event was fired.
      previous: function(attr) {
        if (attr == null || !this._previousAttributes) return null;
        return this._previousAttributes[attr];
      },
  
      // Get all of the attributes of the model at the time of the previous
      // `"change"` event.
      previousAttributes: function() {
        return _.clone(this._previousAttributes);
      },
  
      // Check if the model is currently in a valid state. It's only possible to
      // get into an *invalid* state if you're using silent changes.
      isValid: function(options) {
        return !this.validate || !this.validate(this.attributes, options);
      },
  
      // Run validation against the next complete set of model attributes,
      // returning `true` if all is well. If a specific `error` callback has
      // been passed, call that instead of firing the general `"error"` event.
      _validate: function(attrs, options) {
        if (options && options.silent || !this.validate) return true;
        attrs = _.extend({}, this.attributes, attrs);
        var error = this.validate(attrs, options);
        if (!error) return true;
        if (options && options.error) options.error(this, error, options);
        this.trigger('error', this, error, options);
        return false;
      }
  
    });
  
    // Backbone.Collection
    // -------------------
  
    // Provides a standard collection class for our sets of models, ordered
    // or unordered. If a `comparator` is specified, the Collection will maintain
    // its models in sort order, as they're added and removed.
    var Collection = Backbone.Collection = function(models, options) {
      options || (options = {});
      if (options.model) this.model = options.model;
      if (options.comparator !== void 0) this.comparator = options.comparator;
      this._reset();
      this.initialize.apply(this, arguments);
      if (models) {
        if (options.parse) models = this.parse(models);
        this.reset(models, {silent: true, parse: options.parse});
      }
    };
  
    // Define the Collection's inheritable methods.
    _.extend(Collection.prototype, Events, {
  
      // The default model for a collection is just a **Backbone.Model**.
      // This should be overridden in most cases.
      model: Model,
  
      // Initialize is an empty function by default. Override it with your own
      // initialization logic.
      initialize: function(){},
  
      // The JSON representation of a Collection is an array of the
      // models' attributes.
      toJSON: function(options) {
        return this.map(function(model){ return model.toJSON(options); });
      },
  
      // Proxy `Backbone.sync` by default.
      sync: function() {
        return Backbone.sync.apply(this, arguments);
      },
  
      // Add a model, or list of models to the set. Pass **silent** to avoid
      // firing the `add` event for every new model.
      add: function(models, options) {
        var i, args, length, model, existing;
        var at = options && options.at;
        models = _.isArray(models) ? models.slice() : [models];
  
        // Begin by turning bare objects into model references, and preventing
        // invalid models from being added.
        for (i = 0, length = models.length; i < length; i++) {
          if (models[i] = this._prepareModel(models[i], options)) continue;
          throw new Error("Can't add an invalid model to a collection");
        }
  
        for (i = models.length - 1; i >= 0; i--) {
          model = models[i];
          existing = model.id != null && this._byId[model.id];
  
          // If a duplicate is found, splice it out and optionally merge it into
          // the existing model.
          if (existing || this._byCid[model.cid]) {
            if (options && options.merge && existing) {
              existing.set(model, options);
            }
            models.splice(i, 1);
            continue;
          }
  
          // Listen to added models' events, and index models for lookup by
          // `id` and by `cid`.
          model.on('all', this._onModelEvent, this);
          this._byCid[model.cid] = model;
          if (model.id != null) this._byId[model.id] = model;
        }
  
        // Update `length` and splice in new models.
        this.length += models.length;
        args = [at != null ? at : this.models.length, 0];
        push.apply(args, models);
        splice.apply(this.models, args);
  
        // Sort the collection if appropriate.
        if (this.comparator && at == null) this.sort({silent: true});
  
        if (options && options.silent) return this;
  
        // Trigger `add` events.
        while (model = models.shift()) {
          model.trigger('add', model, this, options);
        }
  
        return this;
      },
  
      // Remove a model, or a list of models from the set. Pass silent to avoid
      // firing the `remove` event for every model removed.
      remove: function(models, options) {
        var i, l, index, model;
        options || (options = {});
        models = _.isArray(models) ? models.slice() : [models];
        for (i = 0, l = models.length; i < l; i++) {
          model = this.getByCid(models[i]) || this.get(models[i]);
          if (!model) continue;
          delete this._byId[model.id];
          delete this._byCid[model.cid];
          index = this.indexOf(model);
          this.models.splice(index, 1);
          this.length--;
          if (!options.silent) {
            options.index = index;
            model.trigger('remove', model, this, options);
          }
          this._removeReference(model);
        }
        return this;
      },
  
      // Add a model to the end of the collection.
      push: function(model, options) {
        model = this._prepareModel(model, options);
        this.add(model, options);
        return model;
      },
  
      // Remove a model from the end of the collection.
      pop: function(options) {
        var model = this.at(this.length - 1);
        this.remove(model, options);
        return model;
      },
  
      // Add a model to the beginning of the collection.
      unshift: function(model, options) {
        model = this._prepareModel(model, options);
        this.add(model, _.extend({at: 0}, options));
        return model;
      },
  
      // Remove a model from the beginning of the collection.
      shift: function(options) {
        var model = this.at(0);
        this.remove(model, options);
        return model;
      },
  
      // Slice out a sub-array of models from the collection.
      slice: function(begin, end) {
        return this.models.slice(begin, end);
      },
  
      // Get a model from the set by id.
      get: function(id) {
        if (id == null) return void 0;
        return this._byId[id.id != null ? id.id : id];
      },
  
      // Get a model from the set by client id.
      getByCid: function(cid) {
        return cid && this._byCid[cid.cid || cid];
      },
  
      // Get the model at the given index.
      at: function(index) {
        return this.models[index];
      },
  
      // Return models with matching attributes. Useful for simple cases of `filter`.
      where: function(attrs) {
        if (_.isEmpty(attrs)) return [];
        return this.filter(function(model) {
          for (var key in attrs) {
            if (attrs[key] !== model.get(key)) return false;
          }
          return true;
        });
      },
  
      // Force the collection to re-sort itself. You don't need to call this under
      // normal circumstances, as the set will maintain sort order as each item
      // is added.
      sort: function(options) {
        if (!this.comparator) {
          throw new Error('Cannot sort a set without a comparator');
        }
  
        if (_.isString(this.comparator) || this.comparator.length === 1) {
          this.models = this.sortBy(this.comparator, this);
        } else {
          this.models.sort(_.bind(this.comparator, this));
        }
  
        if (!options || !options.silent) this.trigger('reset', this, options);
        return this;
      },
  
      // Pluck an attribute from each model in the collection.
      pluck: function(attr) {
        return _.invoke(this.models, 'get', attr);
      },
  
      // When you have more items than you want to add or remove individually,
      // you can reset the entire set with a new list of models, without firing
      // any `add` or `remove` events. Fires `reset` when finished.
      reset: function(models, options) {
        for (var i = 0, l = this.models.length; i < l; i++) {
          this._removeReference(this.models[i]);
        }
        this._reset();
        if (models) this.add(models, _.extend({silent: true}, options));
        if (!options || !options.silent) this.trigger('reset', this, options);
        return this;
      },
  
      // Fetch the default set of models for this collection, resetting the
      // collection when they arrive. If `add: true` is passed, appends the
      // models to the collection instead of resetting.
      fetch: function(options) {
        options = options ? _.clone(options) : {};
        if (options.parse === void 0) options.parse = true;
        var collection = this;
        var success = options.success;
        options.success = function(resp, status, xhr) {
          collection[options.add ? 'add' : 'reset'](collection.parse(resp, xhr), options);
          if (success) success(collection, resp, options);
        };
        return this.sync('read', this, options);
      },
  
      // Create a new instance of a model in this collection. Add the model to the
      // collection immediately, unless `wait: true` is passed, in which case we
      // wait for the server to agree.
      create: function(model, options) {
        var collection = this;
        options = options ? _.clone(options) : {};
        model = this._prepareModel(model, options);
        if (!model) return false;
        if (!options.wait) collection.add(model, options);
        var success = options.success;
        options.success = function(model, resp, options) {
          if (options.wait) collection.add(model, options);
          if (success) success(model, resp, options);
        };
        model.save(null, options);
        return model;
      },
  
      // **parse** converts a response into a list of models to be added to the
      // collection. The default implementation is just to pass it through.
      parse: function(resp, xhr) {
        return resp;
      },
  
      // Create a new collection with an identical list of models as this one.
      clone: function() {
        return new this.constructor(this.models);
      },
  
      // Proxy to _'s chain. Can't be proxied the same way the rest of the
      // underscore methods are proxied because it relies on the underscore
      // constructor.
      chain: function() {
        return _(this.models).chain();
      },
  
      // Reset all internal state. Called when the collection is reset.
      _reset: function(options) {
        this.length = 0;
        this.models = [];
        this._byId  = {};
        this._byCid = {};
      },
  
      // Prepare a model or hash of attributes to be added to this collection.
      _prepareModel: function(attrs, options) {
        if (attrs instanceof Model) {
          if (!attrs.collection) attrs.collection = this;
          return attrs;
        }
        options || (options = {});
        options.collection = this;
        var model = new this.model(attrs, options);
        if (!model._validate(model.attributes, options)) return false;
        return model;
      },
  
      // Internal method to remove a model's ties to a collection.
      _removeReference: function(model) {
        if (this === model.collection) delete model.collection;
        model.off('all', this._onModelEvent, this);
      },
  
      // Internal method called every time a model in the set fires an event.
      // Sets need to update their indexes when models change ids. All other
      // events simply proxy through. "add" and "remove" events that originate
      // in other collections are ignored.
      _onModelEvent: function(event, model, collection, options) {
        if ((event === 'add' || event === 'remove') && collection !== this) return;
        if (event === 'destroy') this.remove(model, options);
        if (model && event === 'change:' + model.idAttribute) {
          delete this._byId[model.previous(model.idAttribute)];
          if (model.id != null) this._byId[model.id] = model;
        }
        this.trigger.apply(this, arguments);
      }
  
    });
  
    // Underscore methods that we want to implement on the Collection.
    var methods = ['forEach', 'each', 'map', 'collect', 'reduce', 'foldl',
      'inject', 'reduceRight', 'foldr', 'find', 'detect', 'filter', 'select',
      'reject', 'every', 'all', 'some', 'any', 'include', 'contains', 'invoke',
      'max', 'min', 'sortedIndex', 'toArray', 'size', 'first', 'head', 'take',
      'initial', 'rest', 'tail', 'last', 'without', 'indexOf', 'shuffle',
      'lastIndexOf', 'isEmpty'];
  
    // Mix in each Underscore method as a proxy to `Collection#models`.
    _.each(methods, function(method) {
      Collection.prototype[method] = function() {
        var args = slice.call(arguments);
        args.unshift(this.models);
        return _[method].apply(_, args);
      };
    });
  
    // Underscore methods that take a property name as an argument.
    var attributeMethods = ['groupBy', 'countBy', 'sortBy'];
  
    // Use attributes instead of properties.
    _.each(attributeMethods, function(method) {
      Collection.prototype[method] = function(value, context) {
        var iterator = _.isFunction(value) ? value : function(model) {
          return model.get(value);
        };
        return _[method](this.models, iterator, context);
      };
    });
  
    // Backbone.Router
    // ---------------
  
    // Routers map faux-URLs to actions, and fire events when routes are
    // matched. Creating a new one sets its `routes` hash, if not set statically.
    var Router = Backbone.Router = function(options) {
      options || (options = {});
      if (options.routes) this.routes = options.routes;
      this._bindRoutes();
      this.initialize.apply(this, arguments);
    };
  
    // Cached regular expressions for matching named param parts and splatted
    // parts of route strings.
    var optionalParam = /\((.*?)\)/g;
    var namedParam    = /:\w+/g;
    var splatParam    = /\*\w+/g;
    var escapeRegExp  = /[-{}[\]+?.,\\^$|#\s]/g;
  
    // Set up all inheritable **Backbone.Router** properties and methods.
    _.extend(Router.prototype, Events, {
  
      // Initialize is an empty function by default. Override it with your own
      // initialization logic.
      initialize: function(){},
  
      // Manually bind a single named route to a callback. For example:
      //
      //     this.route('search/:query/p:num', 'search', function(query, num) {
      //       ...
      //     });
      //
      route: function(route, name, callback) {
        if (!_.isRegExp(route)) route = this._routeToRegExp(route);
        if (!callback) callback = this[name];
        Backbone.history.route(route, _.bind(function(fragment) {
          var args = this._extractParameters(route, fragment);
          callback && callback.apply(this, args);
          this.trigger.apply(this, ['route:' + name].concat(args));
          Backbone.history.trigger('route', this, name, args);
        }, this));
        return this;
      },
  
      // Simple proxy to `Backbone.history` to save a fragment into the history.
      navigate: function(fragment, options) {
        Backbone.history.navigate(fragment, options);
        return this;
      },
  
      // Bind all defined routes to `Backbone.history`. We have to reverse the
      // order of the routes here to support behavior where the most general
      // routes can be defined at the bottom of the route map.
      _bindRoutes: function() {
        if (!this.routes) return;
        var route, routes = _.keys(this.routes);
        while ((route = routes.pop()) != null) {
          this.route(route, this.routes[route]);
        }
      },
  
      // Convert a route string into a regular expression, suitable for matching
      // against the current location hash.
      _routeToRegExp: function(route) {
        route = route.replace(escapeRegExp, '\\$&')
                     .replace(optionalParam, '(?:$1)?')
                     .replace(namedParam, '([^\/]+)')
                     .replace(splatParam, '(.*?)');
        return new RegExp('^' + route + '$');
      },
  
      // Given a route, and a URL fragment that it matches, return the array of
      // extracted parameters.
      _extractParameters: function(route, fragment) {
        return route.exec(fragment).slice(1);
      }
  
    });
  
    // Backbone.History
    // ----------------
  
    // Handles cross-browser history management, based on URL fragments. If the
    // browser does not support `onhashchange`, falls back to polling.
    var History = Backbone.History = function() {
      this.handlers = [];
      _.bindAll(this, 'checkUrl');
  
      // #1653 - Ensure that `History` can be used outside of the browser.
      if (typeof window !== 'undefined') {
        this.location = window.location;
        this.history = window.history;
      }
    };
  
    // Cached regex for cleaning leading hashes and slashes.
    var routeStripper = /^[#\/]/;
  
    // Cached regex for stripping leading and trailing slashes.
    var rootStripper = /^\/+|\/+$/g;
  
    // Cached regex for detecting MSIE.
    var isExplorer = /msie [\w.]+/;
  
    // Cached regex for removing a trailing slash.
    var trailingSlash = /\/$/;
  
    // Has the history handling already been started?
    History.started = false;
  
    // Set up all inheritable **Backbone.History** properties and methods.
    _.extend(History.prototype, Events, {
  
      // The default interval to poll for hash changes, if necessary, is
      // twenty times a second.
      interval: 50,
  
      // Gets the true hash value. Cannot use location.hash directly due to bug
      // in Firefox where location.hash will always be decoded.
      getHash: function(window) {
        var match = (window || this).location.href.match(/#(.*)$/);
        return match ? match[1] : '';
      },
  
      // Get the cross-browser normalized URL fragment, either from the URL,
      // the hash, or the override.
      getFragment: function(fragment, forcePushState) {
        if (fragment == null) {
          if (this._hasPushState || !this._wantsHashChange || forcePushState) {
            fragment = this.location.pathname;
            var root = this.root.replace(trailingSlash, '');
            if (!fragment.indexOf(root)) fragment = fragment.substr(root.length);
          } else {
            fragment = this.getHash();
          }
        }
        return decodeURIComponent(fragment.replace(routeStripper, ''));
      },
  
      // Start the hash change handling, returning `true` if the current URL matches
      // an existing route, and `false` otherwise.
      start: function(options) {
        if (History.started) throw new Error("Backbone.history has already been started");
        History.started = true;
  
        // Figure out the initial configuration. Do we need an iframe?
        // Is pushState desired ... is it available?
        this.options          = _.extend({}, {root: '/'}, this.options, options);
        this.root             = this.options.root;
        this._wantsHashChange = this.options.hashChange !== false;
        this._wantsPushState  = !!this.options.pushState;
        this._hasPushState    = !!(this.options.pushState && this.history && this.history.pushState);
        var fragment          = this.getFragment();
        var docMode           = document.documentMode;
        var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));
  
        // Normalize root to always include a leading and trailing slash.
        this.root = ('/' + this.root + '/').replace(rootStripper, '/');
  
        if (oldIE && this._wantsHashChange) {
          this.iframe = Backbone.$('<iframe src="javascript:0" tabindex="-1" />').hide().appendTo('body')[0].contentWindow;
          this.navigate(fragment);
        }
  
        // Depending on whether we're using pushState or hashes, and whether
        // 'onhashchange' is supported, determine how we check the URL state.
        if (this._hasPushState) {
          Backbone.$(window).bind('popstate', this.checkUrl);
        } else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {
          Backbone.$(window).bind('hashchange', this.checkUrl);
        } else if (this._wantsHashChange) {
          this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
        }
  
        // Determine if we need to change the base url, for a pushState link
        // opened by a non-pushState browser.
        this.fragment = fragment;
        var loc = this.location;
        var atRoot = loc.pathname.replace(/[^\/]$/, '$&/') === this.root;
  
        // If we've started off with a route from a `pushState`-enabled browser,
        // but we're currently in a browser that doesn't support it...
        if (this._wantsHashChange && this._wantsPushState && !this._hasPushState && !atRoot) {
          this.fragment = this.getFragment(null, true);
          this.location.replace(this.root + this.location.search + '#' + this.fragment);
          // Return immediately as browser will do redirect to new url
          return true;
  
        // Or if we've started out with a hash-based route, but we're currently
        // in a browser where it could be `pushState`-based instead...
        } else if (this._wantsPushState && this._hasPushState && atRoot && loc.hash) {
          this.fragment = this.getHash().replace(routeStripper, '');
          this.history.replaceState({}, document.title, this.root + this.fragment + loc.search);
        }
  
        if (!this.options.silent) return this.loadUrl();
      },
  
      // Disable Backbone.history, perhaps temporarily. Not useful in a real app,
      // but possibly useful for unit testing Routers.
      stop: function() {
        Backbone.$(window).unbind('popstate', this.checkUrl).unbind('hashchange', this.checkUrl);
        clearInterval(this._checkUrlInterval);
        History.started = false;
      },
  
      // Add a route to be tested when the fragment changes. Routes added later
      // may override previous routes.
      route: function(route, callback) {
        this.handlers.unshift({route: route, callback: callback});
      },
  
      // Checks the current URL to see if it has changed, and if it has,
      // calls `loadUrl`, normalizing across the hidden iframe.
      checkUrl: function(e) {
        var current = this.getFragment();
        if (current === this.fragment && this.iframe) {
          current = this.getFragment(this.getHash(this.iframe));
        }
        if (current === this.fragment) return false;
        if (this.iframe) this.navigate(current);
        this.loadUrl() || this.loadUrl(this.getHash());
      },
  
      // Attempt to load the current URL fragment. If a route succeeds with a
      // match, returns `true`. If no defined routes matches the fragment,
      // returns `false`.
      loadUrl: function(fragmentOverride) {
        var fragment = this.fragment = this.getFragment(fragmentOverride);
        var matched = _.any(this.handlers, function(handler) {
          if (handler.route.test(fragment)) {
            handler.callback(fragment);
            return true;
          }
        });
        return matched;
      },
  
      // Save a fragment into the hash history, or replace the URL state if the
      // 'replace' option is passed. You are responsible for properly URL-encoding
      // the fragment in advance.
      //
      // The options object can contain `trigger: true` if you wish to have the
      // route callback be fired (not usually desirable), or `replace: true`, if
      // you wish to modify the current URL without adding an entry to the history.
      navigate: function(fragment, options) {
        if (!History.started) return false;
        if (!options || options === true) options = {trigger: options};
        fragment = this.getFragment(fragment || '');
        if (this.fragment === fragment) return;
        this.fragment = fragment;
        var url = this.root + fragment;
  
        // If pushState is available, we use it to set the fragment as a real URL.
        if (this._hasPushState) {
          this.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, url);
  
        // If hash changes haven't been explicitly disabled, update the hash
        // fragment to store history.
        } else if (this._wantsHashChange) {
          this._updateHash(this.location, fragment, options.replace);
          if (this.iframe && (fragment !== this.getFragment(this.getHash(this.iframe)))) {
            // Opening and closing the iframe tricks IE7 and earlier to push a
            // history entry on hash-tag change.  When replace is true, we don't
            // want this.
            if(!options.replace) this.iframe.document.open().close();
            this._updateHash(this.iframe.location, fragment, options.replace);
          }
  
        // If you've told us that you explicitly don't want fallback hashchange-
        // based history, then `navigate` becomes a page refresh.
        } else {
          return this.location.assign(url);
        }
        if (options.trigger) this.loadUrl(fragment);
      },
  
      // Update the hash location, either replacing the current entry, or adding
      // a new one to the browser history.
      _updateHash: function(location, fragment, replace) {
        if (replace) {
          var href = location.href.replace(/(javascript:|#).*$/, '');
          location.replace(href + '#' + fragment);
        } else {
          // #1649 - Some browsers require that `hash` contains a leading #.
          location.hash = '#' + fragment;
        }
      }
  
    });
  
    // Create the default Backbone.history.
    Backbone.history = new History;
  
    // Backbone.View
    // -------------
  
    // Creating a Backbone.View creates its initial element outside of the DOM,
    // if an existing element is not provided...
    var View = Backbone.View = function(options) {
      this.cid = _.uniqueId('view');
      this._configure(options || {});
      this._ensureElement();
      this.initialize.apply(this, arguments);
      this.delegateEvents();
    };
  
    // Cached regex to split keys for `delegate`.
    var delegateEventSplitter = /^(\S+)\s*(.*)$/;
  
    // List of view options to be merged as properties.
    var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName'];
  
    // Set up all inheritable **Backbone.View** properties and methods.
    _.extend(View.prototype, Events, {
  
      // The default `tagName` of a View's element is `"div"`.
      tagName: 'div',
  
      // jQuery delegate for element lookup, scoped to DOM elements within the
      // current view. This should be prefered to global lookups where possible.
      $: function(selector) {
        return this.$el.find(selector);
      },
  
      // Initialize is an empty function by default. Override it with your own
      // initialization logic.
      initialize: function(){},
  
      // **render** is the core function that your view should override, in order
      // to populate its element (`this.el`), with the appropriate HTML. The
      // convention is for **render** to always return `this`.
      render: function() {
        return this;
      },
  
      // Clean up references to this view in order to prevent latent effects and
      // memory leaks.
      dispose: function() {
        this.undelegateEvents();
        if (this.model && this.model.off) this.model.off(null, null, this);
        if (this.collection && this.collection.off) this.collection.off(null, null, this);
        return this;
      },
  
      // Remove this view from the DOM. Note that the view isn't present in the
      // DOM by default, so calling this method may be a no-op.
      remove: function() {
        this.dispose();
        this.$el.remove();
        return this;
      },
  
      // For small amounts of DOM Elements, where a full-blown template isn't
      // needed, use **make** to manufacture elements, one at a time.
      //
      //     var el = this.make('li', {'class': 'row'}, this.model.escape('title'));
      //
      make: function(tagName, attributes, content) {
        var el = document.createElement(tagName);
        if (attributes) Backbone.$(el).attr(attributes);
        if (content != null) Backbone.$(el).html(content);
        return el;
      },
  
      // Change the view's element (`this.el` property), including event
      // re-delegation.
      setElement: function(element, delegate) {
        if (this.$el) this.undelegateEvents();
        this.$el = element instanceof Backbone.$ ? element : Backbone.$(element);
        this.el = this.$el[0];
        if (delegate !== false) this.delegateEvents();
        return this;
      },
  
      // Set callbacks, where `this.events` is a hash of
      //
      // *{"event selector": "callback"}*
      //
      //     {
      //       'mousedown .title':  'edit',
      //       'click .button':     'save'
      //       'click .open':       function(e) { ... }
      //     }
      //
      // pairs. Callbacks will be bound to the view, with `this` set properly.
      // Uses event delegation for efficiency.
      // Omitting the selector binds the event to `this.el`.
      // This only works for delegate-able events: not `focus`, `blur`, and
      // not `change`, `submit`, and `reset` in Internet Explorer.
      delegateEvents: function(events) {
        if (!(events || (events = _.result(this, 'events')))) return;
        this.undelegateEvents();
        for (var key in events) {
          var method = events[key];
          if (!_.isFunction(method)) method = this[events[key]];
          if (!method) throw new Error('Method "' + events[key] + '" does not exist');
          var match = key.match(delegateEventSplitter);
          var eventName = match[1], selector = match[2];
          method = _.bind(method, this);
          eventName += '.delegateEvents' + this.cid;
          if (selector === '') {
            this.$el.bind(eventName, method);
          } else {
            this.$el.delegate(selector, eventName, method);
          }
        }
      },
  
      // Clears all callbacks previously bound to the view with `delegateEvents`.
      // You usually don't need to use this, but may wish to if you have multiple
      // Backbone views attached to the same DOM element.
      undelegateEvents: function() {
        this.$el.unbind('.delegateEvents' + this.cid);
      },
  
      // Performs the initial configuration of a View with a set of options.
      // Keys with special meaning *(model, collection, id, className)*, are
      // attached directly to the view.
      _configure: function(options) {
        if (this.options) options = _.extend({}, this.options, options);
        _.extend(this, _.pick(options, viewOptions));
        this.options = options;
      },
  
      // Ensure that the View has a DOM element to render into.
      // If `this.el` is a string, pass it through `$()`, take the first
      // matching element, and re-assign it to `el`. Otherwise, create
      // an element from the `id`, `className` and `tagName` properties.
      _ensureElement: function() {
        if (!this.el) {
          var attrs = _.extend({}, _.result(this, 'attributes'));
          if (this.id) attrs.id = _.result(this, 'id');
          if (this.className) attrs['class'] = _.result(this, 'className');
          this.setElement(this.make(_.result(this, 'tagName'), attrs), false);
        } else {
          this.setElement(_.result(this, 'el'), false);
        }
      }
  
    });
  
    // Backbone.sync
    // -------------
  
    // Map from CRUD to HTTP for our default `Backbone.sync` implementation.
    var methodMap = {
      'create': 'POST',
      'update': 'PUT',
      'delete': 'DELETE',
      'read':   'GET'
    };
  
    // Override this function to change the manner in which Backbone persists
    // models to the server. You will be passed the type of request, and the
    // model in question. By default, makes a RESTful Ajax request
    // to the model's `url()`. Some possible customizations could be:
    //
    // * Use `setTimeout` to batch rapid-fire updates into a single request.
    // * Send up the models as XML instead of JSON.
    // * Persist models via WebSockets instead of Ajax.
    //
    // Turn on `Backbone.emulateHTTP` in order to send `PUT` and `DELETE` requests
    // as `POST`, with a `_method` parameter containing the true HTTP method,
    // as well as all requests with the body as `application/x-www-form-urlencoded`
    // instead of `application/json` with the model in a param named `model`.
    // Useful when interfacing with server-side languages like **PHP** that make
    // it difficult to read the body of `PUT` requests.
    Backbone.sync = function(method, model, options) {
      var type = methodMap[method];
  
      // Default options, unless specified.
      options || (options = {});
  
      // Default JSON-request options.
      var params = {type: type, dataType: 'json'};
  
      // Ensure that we have a URL.
      if (!options.url) {
        params.url = _.result(model, 'url') || urlError();
      }
  
      // Ensure that we have the appropriate request data.
      if (!options.data && model && (method === 'create' || method === 'update')) {
        params.contentType = 'application/json';
        params.data = JSON.stringify(model);
      }
  
      // For older servers, emulate JSON by encoding the request into an HTML-form.
      if (Backbone.emulateJSON) {
        params.contentType = 'application/x-www-form-urlencoded';
        params.data = params.data ? {model: params.data} : {};
      }
  
      // For older servers, emulate HTTP by mimicking the HTTP method with `_method`
      // And an `X-HTTP-Method-Override` header.
      if (Backbone.emulateHTTP && (type === 'PUT' || type === 'DELETE')) {
        params.type = 'POST';
        if (Backbone.emulateJSON) params.data._method = type;
        var beforeSend = options.beforeSend;
        options.beforeSend = function(xhr) {
          xhr.setRequestHeader('X-HTTP-Method-Override', type);
          if (beforeSend) return beforeSend.apply(this, arguments);
        };
      }
  
      // Don't process data on a non-GET request.
      if (params.type !== 'GET' && !Backbone.emulateJSON) {
        params.processData = false;
      }
  
      var success = options.success;
      options.success = function(resp, status, xhr) {
        if (success) success(resp, status, xhr);
        model.trigger('sync', model, resp, options);
      };
  
      var error = options.error;
      options.error = function(xhr, status, thrown) {
        if (error) error(model, xhr, options);
        model.trigger('error', model, xhr, options);
      };
  
      // Make the request, allowing the user to override any Ajax options.
      return Backbone.ajax(_.extend(params, options));
    };
  
    // Set the default implementation of `Backbone.ajax` to proxy through to `$`.
    Backbone.ajax = function() {
      return Backbone.$.ajax.apply(Backbone.$, arguments);
    };
  
    // Helpers
    // -------
  
    // Helper function to correctly set up the prototype chain, for subclasses.
    // Similar to `goog.inherits`, but uses a hash of prototype properties and
    // class properties to be extended.
    var extend = function(protoProps, staticProps) {
      var parent = this;
      var child;
  
      // The constructor function for the new subclass is either defined by you
      // (the "constructor" property in your `extend` definition), or defaulted
      // by us to simply call the parent's constructor.
      if (protoProps && _.has(protoProps, 'constructor')) {
        child = protoProps.constructor;
      } else {
        child = function(){ parent.apply(this, arguments); };
      }
  
      // Add static properties to the constructor function, if supplied.
      _.extend(child, parent, staticProps);
  
      // Set the prototype chain to inherit from `parent`, without calling
      // `parent`'s constructor function.
      var Surrogate = function(){ this.constructor = child; };
      Surrogate.prototype = parent.prototype;
      child.prototype = new Surrogate;
  
      // Add prototype properties (instance properties) to the subclass,
      // if supplied.
      if (protoProps) _.extend(child.prototype, protoProps);
  
      // Set a convenience property in case the parent's prototype is needed
      // later.
      child.__super__ = parent.prototype;
  
      return child;
    };
  
    // Set up inheritance for the model, collection, router, view and history.
    Model.extend = Collection.extend = Router.extend = View.extend = History.extend = extend;
  
    // Throw an error when a URL is needed, and none is supplied.
    var urlError = function() {
      throw new Error('A "url" property or function must be specified');
    };
  
    return Backbone;
  }));
  