title: UITableViewAutomaticDimension not working in Xcode 6.3
body: <p>I updated my Xcode to 6.3 along with Swift 1.2, and I made the transition.</p>
  
  <p>Everything works except dynamic row height for table view. I have those on 3 completely different table views, so it probably isn't something else influencing the bug.</p>
  
  <p>I set all of the table views to:</p>
  
  <pre><code>tableView.rowHeight = UITableViewAutomaticDimension
  </code></pre>
  
  <p>and all of my xib files are properly constrained.</p>
  
  <p>Any ideas?</p>