title: FB Login using Swift 3 not returning any values and not get back the user to the App after successful login
body: <p>I'm using <code>iOS 10</code> <code>Swift 3</code> to integrate <code>FB Login</code>. I have followed all steps from <code>Facebook</code> documentation. Now the issue is, after successful login it doesn't returning any values and not get back the user to the app.</p>
  
  <p>Note: The same works perfectly in <code>Swift 2</code>.</p>