title: How to disable the light that appears when touching a UIBarButtonItem?
body: <p>I have a toolbar with a <code>UIBarButtonItem</code> with style: <code>UIBarButtonItemStylePlain</code>.
  I wonder how can I disable the light that appears while touching it?</p>
  
  <p><code>UIButton</code> has <code>showsTouchWhenHighlighted</code> property but there is no such a thing for <code>UIBarButtonItem</code> is there a work-around you might know?</p>