title: Allowing interaction with a UIView under another UIView
body: <p>Is there a simple way of allowing interaction with a button in a UIView that lies under another UIView - where there are no actual objects from the top UIView on top of the button?   </p>
  
  <p>For instance, at the moment I have a UIView (A) with an object at the top and an object at the bottom of the screen and nothing in the middle.  This sits on top of another UIView that has buttons in the middle (B).  However, I cannot seem to interact with the buttons in the middle of B.</p>
  
  <p>I can see the buttons in B - I've set the background of A to clearColor - but the buttons in B do not seem to receive touches despite the fact that there are no objects from A actually on top of those buttons.</p>
  
  <p><em>EDIT</em> - I still want to be able to interact with the objects in the top UIView</p>
  
  <p>Surely there is a simple way of doing this?</p>