text: //     Underscore.js 1.5.1
  //     http://underscorejs.org
  //     (c) 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
  //     Underscore may be freely distributed under the MIT license.
  
  (function() {
  
      // Baseline setup
      // --------------
  
      // Establish the root object, `window` in the browser, or `global` on the server.
      var root = this;
  
      // Save the previous value of the `_` variable.
      var previousUnderscore = root._;
  
      // Establish the object that gets returned to break out of a loop iteration.
      var breaker = {};
  
      // Save bytes in the minified (but not gzipped) version:
      var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;
  
      // Create quick reference variables for speed access to core prototypes.
      var
          push             = ArrayProto.push,
          slice            = ArrayProto.slice,
          concat           = ArrayProto.concat,
          toString         = ObjProto.toString,
          hasOwnProperty   = ObjProto.hasOwnProperty;
  
      // All **ECMAScript 5** native function implementations that we hope to use
      // are declared here.
      var
          nativeForEach      = ArrayProto.forEach,
          nativeMap          = ArrayProto.map,
          nativeReduce       = ArrayProto.reduce,
          nativeReduceRight  = ArrayProto.reduceRight,
          nativeFilter       = ArrayProto.filter,
          nativeEvery        = ArrayProto.every,
          nativeSome         = ArrayProto.some,
          nativeIndexOf      = ArrayProto.indexOf,
          nativeLastIndexOf  = ArrayProto.lastIndexOf,
          nativeIsArray      = Array.isArray,
          nativeKeys         = Object.keys,
          nativeBind         = FuncProto.bind;
  
      // Create a safe reference to the Underscore object for use below.
      var _ = function(obj) {
          if (obj instanceof _) return obj;
          if (!(this instanceof _)) return new _(obj);
          this._wrapped = obj;
      };
  
      // Export the Underscore object for **Node.js**, with
      // backwards-compatibility for the old `require()` API. If we're in
      // the browser, add `_` as a global object via a string identifier,
      // for Closure Compiler "advanced" mode.
      if (typeof exports !== 'undefined') {
          if (typeof module !== 'undefined' && module.exports) {
              exports = module.exports = _;
          }
          exports._ = _;
      } else {
          root._ = _;
      }
  
      // Current version.
      _.VERSION = '1.5.1';
  
      // Collection Functions
      // --------------------
  
      // The cornerstone, an `each` implementation, aka `forEach`.
      // Handles objects with the built-in `forEach`, arrays, and raw objects.
      // Delegates to **ECMAScript 5**'s native `forEach` if available.
      var each = _.each = _.forEach = function(obj, iterator, context) {
          if (obj == null) return;
          if (nativeForEach && obj.forEach === nativeForEach) {
              obj.forEach(iterator, context);
          } else if (obj.length === +obj.length) {
              for (var i = 0, l = obj.length; i < l; i++) {
                  if (iterator.call(context, obj[i], i, obj) === breaker) return;
              }
          } else {
              for (var key in obj) {
                  if (_.has(obj, key)) {
                      if (iterator.call(context, obj[key], key, obj) === breaker) return;
                  }
              }
          }
      };
  
      // Return the results of applying the iterator to each element.
      // Delegates to **ECMAScript 5**'s native `map` if available.
      _.map = _.collect = function(obj, iterator, context) {
          var results = [];
          if (obj == null) return results;
          if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
          each(obj, function(value, index, list) {
              results.push(iterator.call(context, value, index, list));
          });
          return results;
      };
  
      var reduceError = 'Reduce of empty array with no initial value';
  
      // **Reduce** builds up a single result from a list of values, aka `inject`,
      // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
      _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
          var initial = arguments.length > 2;
          if (obj == null) obj = [];
          if (nativeReduce && obj.reduce === nativeReduce) {
              if (context) iterator = _.bind(iterator, context);
              return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
          }
          each(obj, function(value, index, list) {
              if (!initial) {
                  memo = value;
                  initial = true;
              } else {
                  memo = iterator.call(context, memo, value, index, list);
              }
          });
          if (!initial) throw new TypeError(reduceError);
          return memo;
      };
  
      // The right-associative version of reduce, also known as `foldr`.
      // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
      _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
          var initial = arguments.length > 2;
          if (obj == null) obj = [];
          if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
              if (context) iterator = _.bind(iterator, context);
              return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
          }
          var length = obj.length;
          if (length !== +length) {
              var keys = _.keys(obj);
              length = keys.length;
          }
          each(obj, function(value, index, list) {
              index = keys ? keys[--length] : --length;
              if (!initial) {
                  memo = obj[index];
                  initial = true;
              } else {
                  memo = iterator.call(context, memo, obj[index], index, list);
              }
          });
          if (!initial) throw new TypeError(reduceError);
          return memo;
      };
  
      // Return the first value which passes a truth test. Aliased as `detect`.
      _.find = _.detect = function(obj, iterator, context) {
          var result;
          any(obj, function(value, index, list) {
              if (iterator.call(context, value, index, list)) {
                  result = value;
                  return true;
              }
          });
          return result;
      };
  
      // Return all the elements that pass a truth test.
      // Delegates to **ECMAScript 5**'s native `filter` if available.
      // Aliased as `select`.
      _.filter = _.select = function(obj, iterator, context) {
          var results = [];
          if (obj == null) return results;
          if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
          each(obj, function(value, index, list) {
              if (iterator.call(context, value, index, list)) results.push(value);
          });
          return results;
      };
  
      // Return all the elements for which a truth test fails.
      _.reject = function(obj, iterator, context) {
          return _.filter(obj, function(value, index, list) {
              return !iterator.call(context, value, index, list);
          }, context);
      };
  
      // Determine whether all of the elements match a truth test.
      // Delegates to **ECMAScript 5**'s native `every` if available.
      // Aliased as `all`.
      _.every = _.all = function(obj, iterator, context) {
          iterator || (iterator = _.identity);
          var result = true;
          if (obj == null) return result;
          if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
          each(obj, function(value, index, list) {
              if (!(result = result && iterator.call(context, value, index, list))) return breaker;
          });
          return !!result;
      };
  
      // Determine if at least one element in the object matches a truth test.
      // Delegates to **ECMAScript 5**'s native `some` if available.
      // Aliased as `any`.
      var any = _.some = _.any = function(obj, iterator, context) {
          iterator || (iterator = _.identity);
          var result = false;
          if (obj == null) return result;
          if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
          each(obj, function(value, index, list) {
              if (result || (result = iterator.call(context, value, index, list))) return breaker;
          });
          return !!result;
      };
  
      // Determine if the array or object contains a given value (using `===`).
      // Aliased as `include`.
      _.contains = _.include = function(obj, target) {
          if (obj == null) return false;
          if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
          return any(obj, function(value) {
              return value === target;
          });
      };
  
      // Invoke a method (with arguments) on every item in a collection.
      _.invoke = function(obj, method) {
          var args = slice.call(arguments, 2);
          var isFunc = _.isFunction(method);
          return _.map(obj, function(value) {
              return (isFunc ? method : value[method]).apply(value, args);
          });
      };
  
      // Convenience version of a common use case of `map`: fetching a property.
      _.pluck = function(obj, key) {
          return _.map(obj, function(value){ return value[key]; });
      };
  
      // Convenience version of a common use case of `filter`: selecting only objects
      // containing specific `key:value` pairs.
      _.where = function(obj, attrs, first) {
          if (_.isEmpty(attrs)) return first ? void 0 : [];
          return _[first ? 'find' : 'filter'](obj, function(value) {
              for (var key in attrs) {
                  if (attrs[key] !== value[key]) return false;
              }
              return true;
          });
      };
  
      // Convenience version of a common use case of `find`: getting the first object
      // containing specific `key:value` pairs.
      _.findWhere = function(obj, attrs) {
          return _.where(obj, attrs, true);
      };
  
      // Return the maximum element or (element-based computation).
      // Can't optimize arrays of integers longer than 65,535 elements.
      // See [WebKit Bug 80797](https://bugs.webkit.org/show_bug.cgi?id=80797)
      _.max = function(obj, iterator, context) {
          if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
              return Math.max.apply(Math, obj);
          }
          if (!iterator && _.isEmpty(obj)) return -Infinity;
          var result = {computed : -Infinity, value: -Infinity};
          each(obj, function(value, index, list) {
              var computed = iterator ? iterator.call(context, value, index, list) : value;
              computed > result.computed && (result = {value : value, computed : computed});
          });
          return result.value;
      };
  
      // Return the minimum element (or element-based computation).
      _.min = function(obj, iterator, context) {
          if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
              return Math.min.apply(Math, obj);
          }
          if (!iterator && _.isEmpty(obj)) return Infinity;
          var result = {computed : Infinity, value: Infinity};
          each(obj, function(value, index, list) {
              var computed = iterator ? iterator.call(context, value, index, list) : value;
              computed < result.computed && (result = {value : value, computed : computed});
          });
          return result.value;
      };
  
      // Shuffle an array.
      _.shuffle = function(obj) {
          var rand;
          var index = 0;
          var shuffled = [];
          each(obj, function(value) {
              rand = _.random(index++);
              shuffled[index - 1] = shuffled[rand];
              shuffled[rand] = value;
          });
          return shuffled;
      };
  
      // An internal function to generate lookup iterators.
      var lookupIterator = function(value) {
          return _.isFunction(value) ? value : function(obj){ return obj[value]; };
      };
  
      // Sort the object's values by a criterion produced by an iterator.
      _.sortBy = function(obj, value, context) {
          var iterator = lookupIterator(value);
          return _.pluck(_.map(obj, function(value, index, list) {
              return {
                  value : value,
                  index : index,
                  criteria : iterator.call(context, value, index, list)
              };
          }).sort(function(left, right) {
                  var a = left.criteria;
                  var b = right.criteria;
                  if (a !== b) {
                      if (a > b || a === void 0) return 1;
                      if (a < b || b === void 0) return -1;
                  }
                  return left.index < right.index ? -1 : 1;
              }), 'value');
      };
  
      // An internal function used for aggregate "group by" operations.
      var group = function(obj, value, context, behavior) {
          var result = {};
          var iterator = lookupIterator(value == null ? _.identity : value);
          each(obj, function(value, index) {
              var key = iterator.call(context, value, index, obj);
              behavior(result, key, value);
          });
          return result;
      };
  
      // Groups the object's values by a criterion. Pass either a string attribute
      // to group by, or a function that returns the criterion.
      _.groupBy = function(obj, value, context) {
          return group(obj, value, context, function(result, key, value) {
              (_.has(result, key) ? result[key] : (result[key] = [])).push(value);
          });
      };
  
      // Counts instances of an object that group by a certain criterion. Pass
      // either a string attribute to count by, or a function that returns the
      // criterion.
      _.countBy = function(obj, value, context) {
          return group(obj, value, context, function(result, key) {
              if (!_.has(result, key)) result[key] = 0;
              result[key]++;
          });
      };
  
      // Use a comparator function to figure out the smallest index at which
      // an object should be inserted so as to maintain order. Uses binary search.
      _.sortedIndex = function(array, obj, iterator, context) {
          iterator = iterator == null ? _.identity : lookupIterator(iterator);
          var value = iterator.call(context, obj);
          var low = 0, high = array.length;
          while (low < high) {
              var mid = (low + high) >>> 1;
              iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid;
          }
          return low;
      };
  
      // Safely create a real, live array from anything iterable.
      _.toArray = function(obj) {
          if (!obj) return [];
          if (_.isArray(obj)) return slice.call(obj);
          if (obj.length === +obj.length) return _.map(obj, _.identity);
          return _.values(obj);
      };
  
      // Return the number of elements in an object.
      _.size = function(obj) {
          if (obj == null) return 0;
          return (obj.length === +obj.length) ? obj.length : _.keys(obj).length;
      };
  
      // Array Functions
      // ---------------
  
      // Get the first element of an array. Passing **n** will return the first N
      // values in the array. Aliased as `head` and `take`. The **guard** check
      // allows it to work with `_.map`.
      _.first = _.head = _.take = function(array, n, guard) {
          if (array == null) return void 0;
          return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
      };
  
      // Returns everything but the last entry of the array. Especially useful on
      // the arguments object. Passing **n** will return all the values in
      // the array, excluding the last N. The **guard** check allows it to work with
      // `_.map`.
      _.initial = function(array, n, guard) {
          return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
      };
  
      // Get the last element of an array. Passing **n** will return the last N
      // values in the array. The **guard** check allows it to work with `_.map`.
      _.last = function(array, n, guard) {
          if (array == null) return void 0;
          if ((n != null) && !guard) {
              return slice.call(array, Math.max(array.length - n, 0));
          } else {
              return array[array.length - 1];
          }
      };
  
      // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
      // Especially useful on the arguments object. Passing an **n** will return
      // the rest N values in the array. The **guard**
      // check allows it to work with `_.map`.
      _.rest = _.tail = _.drop = function(array, n, guard) {
          return slice.call(array, (n == null) || guard ? 1 : n);
      };
  
      // Trim out all falsy values from an array.
      _.compact = function(array) {
          return _.filter(array, _.identity);
      };
  
      // Internal implementation of a recursive `flatten` function.
      var flatten = function(input, shallow, output) {
          if (shallow && _.every(input, _.isArray)) {
              return concat.apply(output, input);
          }
          each(input, function(value) {
              if (_.isArray(value) || _.isArguments(value)) {
                  shallow ? push.apply(output, value) : flatten(value, shallow, output);
              } else {
                  output.push(value);
              }
          });
          return output;
      };
  
      // Return a completely flattened version of an array.
      _.flatten = function(array, shallow) {
          return flatten(array, shallow, []);
      };
  
      // Return a version of the array that does not contain the specified value(s).
      _.without = function(array) {
          return _.difference(array, slice.call(arguments, 1));
      };
  
      // Produce a duplicate-free version of the array. If the array has already
      // been sorted, you have the option of using a faster algorithm.
      // Aliased as `unique`.
      _.uniq = _.unique = function(array, isSorted, iterator, context) {
          if (_.isFunction(isSorted)) {
              context = iterator;
              iterator = isSorted;
              isSorted = false;
          }
          var initial = iterator ? _.map(array, iterator, context) : array;
          var results = [];
          var seen = [];
          each(initial, function(value, index) {
              if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) {
                  seen.push(value);
                  results.push(array[index]);
              }
          });
          return results;
      };
  
      // Produce an array that contains the union: each distinct element from all of
      // the passed-in arrays.
      _.union = function() {
          return _.uniq(_.flatten(arguments, true));
      };
  
      // Produce an array that contains every item shared between all the
      // passed-in arrays.
      _.intersection = function(array) {
          var rest = slice.call(arguments, 1);
          console.log(rest)
          return _.filter(_.uniq(array), function(item) {
              return _.every(rest, function(other) {
                  return _.indexOf(other, item) >= 0;
              });
          });
      };
  
      // Take the difference between one array and a number of other arrays.
      // Only the elements present in just the first array will remain.
      _.difference = function(array) {
          var rest = concat.apply(ArrayProto, slice.call(arguments, 1));
          return _.filter(array, function(value){ return !_.contains(rest, value); });
      };
  
      // Zip together multiple lists into a single array -- elements that share
      // an index go together.
      _.zip = function() {
          var length = _.max(_.pluck(arguments, "length").concat(0));
          var results = new Array(length);
          for (var i = 0; i < length; i++) {
              results[i] = _.pluck(arguments, '' + i);
          }
          return results;
      };
  
      // Converts lists into objects. Pass either a single array of `[key, value]`
      // pairs, or two parallel arrays of the same length -- one of keys, and one of
      // the corresponding values.
      _.object = function(list, values) {
          if (list == null) return {};
          var result = {};
          for (var i = 0, l = list.length; i < l; i++) {
              if (values) {
                  result[list[i]] = values[i];
              } else {
                  result[list[i][0]] = list[i][1];
              }
          }
          return result;
      };
  
      // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
      // we need this function. Return the position of the first occurrence of an
      // item in an array, or -1 if the item is not included in the array.
      // Delegates to **ECMAScript 5**'s native `indexOf` if available.
      // If the array is large and already in sort order, pass `true`
      // for **isSorted** to use binary search.
      _.indexOf = function(array, item, isSorted) {
          if (array == null) return -1;
          var i = 0, l = array.length;
          if (isSorted) {
              if (typeof isSorted == 'number') {
                  i = (isSorted < 0 ? Math.max(0, l + isSorted) : isSorted);
              } else {
                  i = _.sortedIndex(array, item);
                  return array[i] === item ? i : -1;
              }
          }
          if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted);
          for (; i < l; i++) if (array[i] === item) return i;
          return -1;
      };
  
      // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
      _.lastIndexOf = function(array, item, from) {
          if (array == null) return -1;
          var hasIndex = from != null;
          if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) {
              return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item);
          }
          var i = (hasIndex ? from : array.length);
          while (i--) if (array[i] === item) return i;
          return -1;
      };
  
      // Generate an integer Array containing an arithmetic progression. A port of
      // the native Python `range()` function. See
      // [the Python documentation](http://docs.python.org/library/functions.html#range).
      _.range = function(start, stop, step) {
          if (arguments.length <= 1) {
              stop = start || 0;
              start = 0;
          }
          step = arguments[2] || 1;
  
          var len = Math.max(Math.ceil((stop - start) / step), 0);
          var idx = 0;
          var range = new Array(len);
  
          while(idx < len) {
              range[idx++] = start;
              start += step;
          }
  
          return range;
      };
  
      // Function (ahem) Functions
      // ------------------
  
      // Reusable constructor function for prototype setting.
      var ctor = function(){};
  
      // Create a function bound to a given object (assigning `this`, and arguments,
      // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
      // available.
      _.bind = function(func, context) {
          var args, bound;
          if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
          if (!_.isFunction(func)) throw new TypeError;
          args = slice.call(arguments, 2);
          return bound = function() {
              if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
              ctor.prototype = func.prototype;
              var self = new ctor;
              ctor.prototype = null;
              var result = func.apply(self, args.concat(slice.call(arguments)));
              if (Object(result) === result) return result;
              return self;
          };
      };
  
      // Partially apply a function by creating a version that has had some of its
      // arguments pre-filled, without changing its dynamic `this` context.
      _.partial = function(func) {
          var args = slice.call(arguments, 1);
          return function() {
              return func.apply(this, args.concat(slice.call(arguments)));
          };
      };
  
      // Bind all of an object's methods to that object. Useful for ensuring that
      // all callbacks defined on an object belong to it.
      _.bindAll = function(obj) {
          var funcs = slice.call(arguments, 1);
          if (funcs.length === 0) throw new Error("bindAll must be passed function names");
          each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
          return obj;
      };
  
      // Memoize an expensive function by storing its results.
      _.memoize = function(func, hasher) {
          var memo = {};
          hasher || (hasher = _.identity);
          return function() {
              var key = hasher.apply(this, arguments);
              return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
          };
      };
  
      // Delays a function for the given number of milliseconds, and then calls
      // it with the arguments supplied.
      _.delay = function(func, wait) {
          var args = slice.call(arguments, 2);
          return setTimeout(function(){ return func.apply(null, args); }, wait);
      };
  
      // Defers a function, scheduling it to run after the current call stack has
      // cleared.
      _.defer = function(func) {
          return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
      };
  
      // Returns a function, that, when invoked, will only be triggered at most once
      // during a given window of time. Normally, the throttled function will run
      // as much as it can, without ever going more than once per `wait` duration;
      // but if you'd like to disable the execution on the leading edge, pass
      // `{leading: false}`. To disable execution on the trailing edge, ditto.
      _.throttle = function(func, wait, options) {
          var context, args, result;
          var timeout = null;
          var previous = 0;
          options || (options = {});
          var later = function() {
              previous = options.leading === false ? 0 : new Date;
              timeout = null;
              result = func.apply(context, args);
          };
          return function() {
              var now = new Date;
              if (!previous && options.leading === false) previous = now;
              var remaining = wait - (now - previous);
              context = this;
              args = arguments;
              if (remaining <= 0) {
                  clearTimeout(timeout);
                  timeout = null;
                  previous = now;
                  result = func.apply(context, args);
              } else if (!timeout && options.trailing !== false) {
                  timeout = setTimeout(later, remaining);
              }
              return result;
          };
      };
  
      // Returns a function, that, as long as it continues to be invoked, will not
      // be triggered. The function will be called after it stops being called for
      // N milliseconds. If `immediate` is passed, trigger the function on the
      // leading edge, instead of the trailing.
      _.debounce = function(func, wait, immediate) {
          var result;
          var timeout = null;
          return function() {
              var context = this, args = arguments;
              var later = function() {
                  timeout = null;
                  if (!immediate) result = func.apply(context, args);
              };
              var callNow = immediate && !timeout;
              clearTimeout(timeout);
              timeout = setTimeout(later, wait);
              if (callNow) result = func.apply(context, args);
              return result;
          };
      };
  
      // Returns a function that will be executed at most one time, no matter how
      // often you call it. Useful for lazy initialization.
      _.once = function(func) {
          var ran = false, memo;
          return function() {
              if (ran) return memo;
              ran = true;
              memo = func.apply(this, arguments);
              func = null;
              return memo;
          };
      };
  
      // Returns the first function passed as an argument to the second,
      // allowing you to adjust arguments, run code before and after, and
      // conditionally execute the original function.
      _.wrap = function(func, wrapper) {
          return function() {
              var args = [func];
              push.apply(args, arguments);
              return wrapper.apply(this, args);
          };
      };
  
      // Returns a function that is the composition of a list of functions, each
      // consuming the return value of the function that follows.
      _.compose = function() {
          var funcs = arguments;
          return function() {
              var args = arguments;
              for (var i = funcs.length - 1; i >= 0; i--) {
                  args = [funcs[i].apply(this, args)];
              }
              return args[0];
          };
      };
  
      // Returns a function that will only be executed after being called N times.
      _.after = function(times, func) {
          return function() {
              if (--times < 1) {
                  return func.apply(this, arguments);
              }
          };
      };
  
      // Object Functions
      // ----------------
  
      // Retrieve the names of an object's properties.
      // Delegates to **ECMAScript 5**'s native `Object.keys`
      _.keys = nativeKeys || function(obj) {
          if (obj !== Object(obj)) throw new TypeError('Invalid object');
          var keys = [];
          for (var key in obj) if (_.has(obj, key)) keys.push(key);
          return keys;
      };
  
      // Retrieve the values of an object's properties.
      _.values = function(obj) {
          var values = [];
          for (var key in obj) if (_.has(obj, key)) values.push(obj[key]);
          return values;
      };
  
      // Convert an object into a list of `[key, value]` pairs.
      _.pairs = function(obj) {
          var pairs = [];
          for (var key in obj) if (_.has(obj, key)) pairs.push([key, obj[key]]);
          return pairs;
      };
  
      // Invert the keys and values of an object. The values must be serializable.
      _.invert = function(obj) {
          var result = {};
          for (var key in obj) if (_.has(obj, key)) result[obj[key]] = key;
          return result;
      };
  
      // Return a sorted list of the function names available on the object.
      // Aliased as `methods`
      _.functions = _.methods = function(obj) {
          var names = [];
          for (var key in obj) {
              if (_.isFunction(obj[key])) names.push(key);
          }
          return names.sort();
      };
  
      // Extend a given object with all the properties in passed-in object(s).
      _.extend = function(obj) {
          each(slice.call(arguments, 1), function(source) {
              if (source) {
                  for (var prop in source) {
                      obj[prop] = source[prop];
                  }
              }
          });
          return obj;
      };
  
      // Return a copy of the object only containing the whitelisted properties.
      _.pick = function(obj) {
          var copy = {};
          var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
          each(keys, function(key) {
              if (key in obj) copy[key] = obj[key];
          });
          return copy;
      };
  
      // Return a copy of the object without the blacklisted properties.
      _.omit = function(obj) {
          var copy = {};
          var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
          for (var key in obj) {
              if (!_.contains(keys, key)) copy[key] = obj[key];
          }
          return copy;
      };
  
      // Fill in a given object with default properties.
      _.defaults = function(obj) {
          each(slice.call(arguments, 1), function(source) {
              if (source) {
                  for (var prop in source) {
                      if (obj[prop] === void 0) obj[prop] = source[prop];
                  }
              }
          });
          return obj;
      };
  
      // Create a (shallow-cloned) duplicate of an object.
      _.clone = function(obj) {
          if (!_.isObject(obj)) return obj;
          return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
      };
  
      // Invokes interceptor with the obj, and then returns obj.
      // The primary purpose of this method is to "tap into" a method chain, in
      // order to perform operations on intermediate results within the chain.
      _.tap = function(obj, interceptor) {
          interceptor(obj);
          return obj;
      };
  
      // Internal recursive comparison function for `isEqual`.
      var eq = function(a, b, aStack, bStack) {
          // Identical objects are equal. `0 === -0`, but they aren't identical.
          // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
          if (a === b) return a !== 0 || 1 / a == 1 / b;
          // A strict comparison is necessary because `null == undefined`.
          if (a == null || b == null) return a === b;
          // Unwrap any wrapped objects.
          if (a instanceof _) a = a._wrapped;
          if (b instanceof _) b = b._wrapped;
          // Compare `[[Class]]` names.
          var className = toString.call(a);
          if (className != toString.call(b)) return false;
          switch (className) {
              // Strings, numbers, dates, and booleans are compared by value.
              case '[object String]':
                  // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
                  // equivalent to `new String("5")`.
                  return a == String(b);
              case '[object Number]':
                  // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
                  // other numeric values.
                  return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
              case '[object Date]':
              case '[object Boolean]':
                  // Coerce dates and booleans to numeric primitive values. Dates are compared by their
                  // millisecond representations. Note that invalid dates with millisecond representations
                  // of `NaN` are not equivalent.
                  return +a == +b;
              // RegExps are compared by their source patterns and flags.
              case '[object RegExp]':
                  return a.source == b.source &&
                      a.global == b.global &&
                      a.multiline == b.multiline &&
                      a.ignoreCase == b.ignoreCase;
          }
          if (typeof a != 'object' || typeof b != 'object') return false;
          // Assume equality for cyclic structures. The algorithm for detecting cyclic
          // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
          var length = aStack.length;
          while (length--) {
              // Linear search. Performance is inversely proportional to the number of
              // unique nested structures.
              if (aStack[length] == a) return bStack[length] == b;
          }
          // Objects with different constructors are not equivalent, but `Object`s
          // from different frames are.
          var aCtor = a.constructor, bCtor = b.constructor;
          if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
              _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
              return false;
          }
          // Add the first object to the stack of traversed objects.
          aStack.push(a);
          bStack.push(b);
          var size = 0, result = true;
          // Recursively compare objects and arrays.
          if (className == '[object Array]') {
              // Compare array lengths to determine if a deep comparison is necessary.
              size = a.length;
              result = size == b.length;
              if (result) {
                  // Deep compare the contents, ignoring non-numeric properties.
                  while (size--) {
                      if (!(result = eq(a[size], b[size], aStack, bStack))) break;
                  }
              }
          } else {
              // Deep compare objects.
              for (var key in a) {
                  if (_.has(a, key)) {
                      // Count the expected number of properties.
                      size++;
                      // Deep compare each member.
                      if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break;
                  }
              }
              // Ensure that both objects contain the same number of properties.
              if (result) {
                  for (key in b) {
                      if (_.has(b, key) && !(size--)) break;
                  }
                  result = !size;
              }
          }
          // Remove the first object from the stack of traversed objects.
          aStack.pop();
          bStack.pop();
          return result;
      };
  
      // Perform a deep comparison to check if two objects are equal.
      _.isEqual = function(a, b) {
          return eq(a, b, [], []);
      };
  
      // Is a given array, string, or object empty?
      // An "empty" object has no enumerable own-properties.
      _.isEmpty = function(obj) {
          if (obj == null) return true;
          if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
          for (var key in obj) if (_.has(obj, key)) return false;
          return true;
      };
  
      // Is a given value a DOM element?
      _.isElement = function(obj) {
          return !!(obj && obj.nodeType === 1);
      };
  
      // Is a given value an array?
      // Delegates to ECMA5's native Array.isArray
      _.isArray = nativeIsArray || function(obj) {
          return toString.call(obj) == '[object Array]';
      };
  
      // Is a given variable an object?
      _.isObject = function(obj) {
          return obj === Object(obj);
      };
  
      // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp.
      each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) {
          _['is' + name] = function(obj) {
              return toString.call(obj) == '[object ' + name + ']';
          };
      });
  
      // Define a fallback version of the method in browsers (ahem, IE), where
      // there isn't any inspectable "Arguments" type.
      if (!_.isArguments(arguments)) {
          _.isArguments = function(obj) {
              return !!(obj && _.has(obj, 'callee'));
          };
      }
  
      // Optimize `isFunction` if appropriate.
      if (typeof (/./) !== 'function') {
          _.isFunction = function(obj) {
              return typeof obj === 'function';
          };
      }
  
      // Is a given object a finite number?
      _.isFinite = function(obj) {
          return isFinite(obj) && !isNaN(parseFloat(obj));
      };
  
      // Is the given value `NaN`? (NaN is the only number which does not equal itself).
      _.isNaN = function(obj) {
          return _.isNumber(obj) && obj != +obj;
      };
  
      // Is a given value a boolean?
      _.isBoolean = function(obj) {
          return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
      };
  
      // Is a given value equal to null?
      _.isNull = function(obj) {
          return obj === null;
      };
  
      // Is a given variable undefined?
      _.isUndefined = function(obj) {
          return obj === void 0;
      };
  
      // Shortcut function for checking if an object has a given property directly
      // on itself (in other words, not on a prototype).
      _.has = function(obj, key) {
          return hasOwnProperty.call(obj, key);
      };
  
      // Utility Functions
      // -----------------
  
      // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
      // previous owner. Returns a reference to the Underscore object.
      _.noConflict = function() {
          root._ = previousUnderscore;
          return this;
      };
  
      // Keep the identity function around for default iterators.
      _.identity = function(value) {
          return value;
      };
  
      // Run a function **n** times.
      _.times = function(n, iterator, context) {
          var accum = Array(Math.max(0, n));
          for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i);
          return accum;
      };
  
      // Return a random integer between min and max (inclusive).
      _.random = function(min, max) {
          if (max == null) {
              max = min;
              min = 0;
          }
          return min + Math.floor(Math.random() * (max - min + 1));
      };
  
      // List of HTML entities for escaping.
      var entityMap = {
          escape: {
              '&': '&amp;',
              '<': '&lt;',
              '>': '&gt;',
              '"': '&quot;',
              "'": '&#x27;',
              '/': '&#x2F;'
          }
      };
      entityMap.unescape = _.invert(entityMap.escape);
  
      // Regexes containing the keys and values listed immediately above.
      var entityRegexes = {
          escape:   new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'),
          unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g')
      };
  
      // Functions for escaping and unescaping strings to/from HTML interpolation.
      _.each(['escape', 'unescape'], function(method) {
          _[method] = function(string) {
              if (string == null) return '';
              return ('' + string).replace(entityRegexes[method], function(match) {
                  return entityMap[method][match];
              });
          };
      });
  
      // If the value of the named `property` is a function then invoke it with the
      // `object` as context; otherwise, return it.
      _.result = function(object, property) {
          if (object == null) return void 0;
          var value = object[property];
          return _.isFunction(value) ? value.call(object) : value;
      };
  
      // Add your own custom functions to the Underscore object.
      _.mixin = function(obj) {
          each(_.functions(obj), function(name){
              var func = _[name] = obj[name];
              _.prototype[name] = function() {
                  var args = [this._wrapped];
                  push.apply(args, arguments);
                  return result.call(this, func.apply(_, args));
              };
          });
      };
  
      // Generate a unique integer id (unique within the entire client session).
      // Useful for temporary DOM ids.
      var idCounter = 0;
      _.uniqueId = function(prefix) {
          var id = ++idCounter + '';
          return prefix ? prefix + id : id;
      };
  
      // By default, Underscore uses ERB-style template delimiters, change the
      // following template settings to use alternative delimiters.
      _.templateSettings = {
          evaluate    : /<%([\s\S]+?)%>/g,
          interpolate : /<%=([\s\S]+?)%>/g,
          escape      : /<%-([\s\S]+?)%>/g
      };
  
      // When customizing `templateSettings`, if you don't want to define an
      // interpolation, evaluation or escaping regex, we need one that is
      // guaranteed not to match.
      var noMatch = /(.)^/;
  
      // Certain characters need to be escaped so that they can be put into a
      // string literal.
      var escapes = {
          "'":      "'",
          '\\':     '\\',
          '\r':     'r',
          '\n':     'n',
          '\t':     't',
          '\u2028': 'u2028',
          '\u2029': 'u2029'
      };
  
      var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g;
  
      // JavaScript micro-templating, similar to John Resig's implementation.
      // Underscore templating handles arbitrary delimiters, preserves whitespace,
      // and correctly escapes quotes within interpolated code.
      _.template = function(text, data, settings) {
          var render;
          settings = _.defaults({}, settings, _.templateSettings);
  
          // Combine delimiters into one regular expression via alternation.
          var matcher = new RegExp([
              (settings.escape || noMatch).source,
              (settings.interpolate || noMatch).source,
              (settings.evaluate || noMatch).source
          ].join('|') + '|$', 'g');
  
          // Compile the template source, escaping string literals appropriately.
          var index = 0;
          var source = "__p+='";
          text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
              source += text.slice(index, offset)
                  .replace(escaper, function(match) { return '\\' + escapes[match]; });
  
              if (escape) {
                  source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
              }
              if (interpolate) {
                  source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
              }
              if (evaluate) {
                  source += "';\n" + evaluate + "\n__p+='";
              }
              index = offset + match.length;
              return match;
          });
          source += "';\n";
  
          // If a variable is not specified, place data values in local scope.
          if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';
  
          source = "var __t,__p='',__j=Array.prototype.join," +
              "print=function(){__p+=__j.call(arguments,'');};\n" +
              source + "return __p;\n";
  
          try {
              render = new Function(settings.variable || 'obj', '_', source);
          } catch (e) {
              e.source = source;
              throw e;
          }
  
          if (data) return render(data, _);
          var template = function(data) {
              return render.call(this, data, _);
          };
  
          // Provide the compiled function source as a convenience for precompilation.
          template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}';
  
          return template;
      };
  
      // Add a "chain" function, which will delegate to the wrapper.
      _.chain = function(obj) {
          return _(obj).chain();
      };
  
      // OOP
      // ---------------
      // If Underscore is called as a function, it returns a wrapped object that
      // can be used OO-style. This wrapper holds altered versions of all the
      // underscore functions. Wrapped objects may be chained.
  
      // Helper function to continue chaining intermediate results.
      var result = function(obj) {
          return this._chain ? _(obj).chain() : obj;
      };
  
      // Add all of the Underscore functions to the wrapper object.
      _.mixin(_);
  
      // Add all mutator Array functions to the wrapper.
      each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
          var method = ArrayProto[name];
          _.prototype[name] = function() {
              var obj = this._wrapped;
              method.apply(obj, arguments);
              if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0];
              return result.call(this, obj);
          };
      });
  
      // Add all accessor Array functions to the wrapper.
      each(['concat', 'join', 'slice'], function(name) {
          var method = ArrayProto[name];
          _.prototype[name] = function() {
              return result.call(this, method.apply(this._wrapped, arguments));
          };
      });
  
      _.extend(_.prototype, {
  
          // Start chaining a wrapped Underscore object.
          chain: function() {
              this._chain = true;
              return this;
          },
  
          // Extracts the result from a wrapped and chained object.
          value: function() {
              return this._wrapped;
          }
  
      });
  
  }).call(this);