title: CollectionView sizeForItemAtIndexPath never called
body: <p>This is driving me crazy! I have a UICollectionViewController as shown below: </p>
  
  <pre><code>class PhrasesCompactCollectionViewController: UICollectionViewController
  </code></pre>
  
  <p>The numberOfSections and cellForItemAt are being called but the sizeForItemAtIndexPath is never called. I am using the same exact code somewhere else and it fires correctly. I am using Xcode 8 Beta 6.</p>
  
  <pre><code>func collectionView(collectionView: UICollectionView,
                          layout collectionViewLayout: UICollectionViewLayout,
                          sizeForItemAtIndexPath indexPath:  NSIndexPath) -&gt; CGSize {
  
          return CGSize(width: 120, height:120) 
      }
  </code></pre>