title: UIView inside UIScrollView not getting touch events
body: <p>My view hierarchy looks like this:</p>
  
  <pre><code>-UIScrollView
  ---UIView
  ------CustomUIView
  ------CustomUIView
  </code></pre>
  
  <p>I have implemented <code>touchesBegan</code> in CustomUIView, but it's not getting called. </p>
  
  <p>Can someone please tell me how I can get my CustomUIView to detect touches?</p>