title: Ember-Data objectAt() to get first result does not work
body: <p>I'm populating two templates with data: the first template has detailed information about the model (called Slider), and the second template has a list of the last 5 sliders.</p>
  
  <p>The problem is that when I use objectAt(0) on the result, the model does not get applied to the template correctly. The other template with the list <em>does</em> get populated. What I mean is this:</p>
  
  <pre><code>App.IndexRoute = Ember.Route.extend({
    setupController: function() {
      var sliders = App.Slider.find({ limit: 5 });
  
      this.controllerFor('indexSlider').set('model', sliders.objectAt(0));
      this.controllerFor('indexSliders').set('model', sliders); // this works fine and loads the data into the template
    }
  });
  </code></pre>
  
  <p>That code does not work. However, it does work when I replace the indexSlider model with this:</p>
  
  <pre><code>App.IndexRoute = Ember.Route.extend({
    setupController: function() {
      var sliders = App.Slider.find({ limit: 5 });
  
      this.controllerFor('indexSlider').set('model', App.Slider.find(52));
      this.controllerFor('indexSliders').set('model', sliders);
    }
  });
  </code></pre>
  
  <p>...where 52 is the ID of the first result. This leads me to think that objectAt doesn't really work properly for rendering the model on the template, or am I just doing it wrong?</p>