title: What happens when popToRootViewController is called?
body: <p>Say I have a stack 3 view controllers deep. If I call <code>popToRootViewController</code> on the <code>navigationController</code>, the top view controller gets <code>viewWillDisappear</code> called but not on the middle controller. Is anything called on the middle controller?</p>
  
  <p>Update: I tried to use dealloc for what I needed but found out that the VCs are deallocated from root+1 to top and not the way you would think a stack would work.</p>