title: Ember.ArrayProxy changes not triggering handlebars #each update
body: <p>I suspect there is a way to update an Ember.Array proxy that will trigger ember's notifications but what I can't figure out how.  </p>
  
  <p>I am overwriting the "content" property to update the array. The array does update but the view does not. </p>
  
  <pre><code>App.items = Ember.ArrayProxy.create({
      content: [
          Ember.Object.create({ name: 'Me', city: 'new york'}),
          Ember.Object.create({ name: 'You', city: 'boston'})
      ],
  
      sortByCity: function() { 
          this.set('content', this.get('content').sort(function(a,b) {
              return a.get('city') &gt; b.get('city')
          }));   
      }
  });
  </code></pre>
  
  <p>Here's a fiddle that demonstrates the problem <a href="http://jsfiddle.net/alexrothenberg/za4Ha/1/" rel="noreferrer">http://jsfiddle.net/alexrothenberg/za4Ha/1/</a></p>
  
  <p>Any help is appreciated. Thanks!</p>