title: Update UIView class in Interface Builder
body: <p>I'm building a UI in XCode interface builder.  After having layed out the required view hierarchy, I realised that one of the views closer to the top of the hierarchy should be a <code>UIScrollView</code> and not a <code>UIView</code>.</p>
  
  <p>Is there any way to easily change that view's type from UIView to UIScrollView without having to re-layout all the child components with their own sub-view hierarchies?</p>