title: UIView hide children views when out of bounds
body: <p>I have a view, lets say 100x100. And it has set of uiviews as subviews: let say 30x30</p>
  
  <p>If a subview has top-left coordinate: (90,90) - I expect to see only part of this subview. But I still see entire area - even if it is out of parents bounds</p>
  
  <p>The question is how to make uiview to show only those parts of subview, which are in original bounds?</p>
  
  <p>thank you</p>