title: UICollectionView cells, auto layout and collectionview layout changes
body: <p>I have a collection view which displays cells looking like a classic table view with image, title and subtitle.</p>
  
  <p>I want to be able to switch the layout to a grid showing only the images, 3 in a row.</p>
  
  <p><img src="https://i.stack.imgur.com/aARaQ.png" alt="Mockup of the two layouts"></p>
  
  <p>The content of the collection view cell is layouted in a storyboard with auto layout. The imageView has the following constraints:</p>
  
  <ul>
  <li>Leading 0 to the left cell edge</li>
  <li>Top 0 to the top cell edge</li>
  <li>Bottom 0 to the bottom cell edge</li>
  <li>Fixed width</li>
  <li>Horizontal space to the labels</li>
  </ul>
  
  <p>After the layout change the imageView should have constraints of zero to all edges of the container, so that it fills it completely.</p>
  
  <p>At the moment when I change the layout the app crashes with <code>Unable to simultaneously satisfy constraints.</code>. What is the best way to fix the constraints when the layout is changed, maybe even replace the cell class?</p>