title: Native driver find from Mongoose model not returning Cursor
body: <p>I'm trying to execute a native MongoDB <code>find</code> query via the <code>collection</code> property of a Mongoose <code>Model</code>.  I'm not supplying a callback so I expect the find to return a <code>Cursor</code> object, but it returns <code>undefined</code> instead.  According to the <a href="https://github.com/learnboost/mongoose" rel="noreferrer">Mongoose docs</a>, the driver being used is accessible via <code>YourModel.collection</code> and if I switch to purely using the native driver code <code>find</code> does return a <code>Cursor</code> so I can't figure out what's going on.</p>
  
  <p>Here's a code snippet that reproduces the problem:</p>
  
  <pre><code>var db = mongoose.connect('localhost', 'test');
  var userSchema = new Schema({
      username: String,
      emailAddress: String
  });
  var User = mongoose.model('user', userSchema);
  
  var cursor = User.collection.find({});
  // cursor will be set to undefined
  </code></pre>
  
  <p>I've tried to step into the code with node-inspector, but it's not letting me.  Any idea what I'm doing wrong?</p>