title: UICollectionView with custom layout - how/where to add a supplementary view programmatically?
body: <p>I'm working with an example of <a href="https://github.com/mpospese/CircleLayout" rel="nofollow">Circle Layout</a>, using UICollectionView with a custom layout class defined in the storyboard. </p>
  
  <p><strong>Is there some sort of a tutorial or a step by step explanation of how to add a supplementary view over to a collection view that uses a custom layout?</strong> </p>
  
  <p>I've been looking at the <a href="https://github.com/mpospese/IntroducingCollectionViews" rel="nofollow">Introducing Collection Views</a> example, but cannot really understand how supplementary views are defined in that project. It appears that they are registered in a storyboard using flow layout, but I'm at a loss as to how subsequent layout changes in that project move supplementary views around. </p>