title: Transform (rotate) a UIBarButtonItem
body: <p>Does anybody know how to transform a UIBarButtonItem ?</p>
  
  <p>I tried this but with no results :(
  It's not working on both UIBarButtonItem and its customview.</p>
  
  <pre>
  [UIView beginAnimations:nil context:NULL];
  [UIView setAnimationDuration:5.0f];
  CGAffineTransform myTransform = CGAffineTransformMakeRotation(M_PI_2);
  UIBarButtonItem * currentItem =  [self.toolbarItems objectAtIndex:4];
  currentItem.customView.transform = myTransform;
  [UIView commitAnimations];
  </pre>
  
  <p>I confirm the transform works on other views (I tried with self.view).</p>
  
  <p>Thanks !</p>