title: How to animate single UICollectionView cell with duration
body: <p>I am trying to animate the first cell's height and the rest to scroll up or down. Inside the cell is an image view with .ScaleAspectFill</p>
  
  <p>I manage to do it if the transition is interactive with invalidateLayout() and sizeForItemAtIndexPath, but I can't figure out how to animate to an end state</p>
  
  <p>Here's what I'm doing:</p>
  
  <pre><code>let cell = collectionView!.cellForItemAtIndexPath(NSIndexPath(forItem: 0,    inSection: 0)) as! HomeFeedCell
  var size:CGSize = getNewSize(cell)
  
  UIView.transitionWithView(collectionView!, duration: duration, options: .CurveEaseOut | .LayoutSubviews, animations: {
                  cell.frame.size.height = size.height
              }, completion: nil)
  </code></pre>
  
  <p>This animates the first cell but doesn't move the rest of the cells. I tried invalidateLayout() or reloading the visible cells inside the animation block but it gives strange result</p>