title: Move up keyboard when editing UITextField on iOS9
body: <p>For my keyboards to move up to uncover <code>UITextField</code> in my iOS app, I used to implement this answer: <a href="https://stackoverflow.com/a/6908258/3855618">https://stackoverflow.com/a/6908258/3855618</a> on iOS7 and 8 and it has worked perfectly for now. However on iOS 9.1, it doesn't work anymore.</p>
  
  <p>To be more accurate, even if the background view does move up, the <code>UITextField</code> doesn't.</p>
  
  <p>Any idea of what has changed so much since iOS9 and iOS 9.1?</p>