title: Registering for remote notifications when a user signs in
body: <p>I'd want my app to only receive remote notifications when the user has signed in. I've been reading Apple's <a href="https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/IPhoneOSClientImp.html#//apple_ref/doc/uid/TP40008194-CH103-SW2" rel="nofollow">Local and Remote Notification Programming Guide</a>, and I'm not sure if it is required to call <code>registerUserNotificationSettings:</code> when the app launches (<code>application:didFinishLaunchingWithOptions:</code>), or that is just an example and I can register for remote notifications once the user has signed in (if he does).</p>
  
  <p>On the other hand, if I want to stop receiving remote notifications when the user signs out... is it possible to "unregister" the app?</p>
  
  <p>Thanks</p>