title: Black Color Behind UIView while UIView Transition Animation
body: <p>I am doing transition animation using the following block. But I observed that during flip animation a black color layer appears beneath the UIView. Is there any way to set custom color to that layer.   </p>
  
  <pre><code>UIView.transitionWithView(ibContainerView, duration: 0.2, options: [.CurveEaseOut,.TransitionFlipFromLeft], animations: {
                  self.ibContainerView.addSubview(self.ibInstagramView)
  
                  }, completion:nil)
  
          }
  </code></pre>