title: Ember transition & rendering complete event
body: <p>Is there any event fired stating the transition/rendering has completed (and the dom is visible/ready).</p>
  
  <p>setupcontroller/activate are before the dom is built/rendered</p>
  
  <p>didInsertElement gets fired only the first time when I've already inserted an element and I'm just switching the model out underneath it.</p>
  
  <p>What I'm really looking for is the transition is complete event</p>
  
  <p>I guess I can do this, but I was kind of hoping it was already built in...</p>
  
  <pre><code>Ember.Router.reopen({
    didTransition:function(infos) {
       this._super(infos);
       console.log('transition complete');  
    }
  });
  </code></pre>
  
  <p>Even cooler would be a callback to the route that the transition completed for it, I may have to write this and submit a pull request.</p>