title: UIBarButtonItem with UIButton as CustomView - from UIButton, how to access the UIBarButtonItem its in?
body: <p>I have a <code>UIBarButtonItem</code> with <code>UIButton</code> as custom view. </p>
  
  <p>The <code>UIButton</code> has a <code>addTarget:action:</code> on it. In the action I present a popover. I'm currently presenting from the <code>sender.frame</code> (the <code>UIButton</code>'s Frame)  I want to Present from the <code>UIBarButtonItem</code> instead.</p>
  
  <p>How can I access the <code>UIBarButtonItem</code> from the <code>UIButton</code>?</p>