title: Push notification custom sound not played instead of default sound
body: <p>My problem is here:</p>
  
  <p>I use Parse Push Notifications services, all works fine, I receive local notifications on the device, all works, but now the problem is at that point: the custom sound isn't played, instead, this is the default iOS notification sound that is played.</p>
  
  <p>All is done in the rules, I have a supported packaged sound in ".wav" verified with QuickTime player that confirmed the custom sound file is in "PCM linear" format.</p>
  
  <p>The sound file, is correctly present in  the main bundle of the application and copied if needed in copy bundle resources (furthermore, the code in AppDelegate is looking correct)</p>
  
  <p>I show you the code for more details:</p>
  
  <pre><code>NSDictionary *data = [NSDictionary dictionaryWithObjectsAndKeys:
      @"You have received an coin !", @"alert",
      @"Increment", @"badge",
      @"custom_bell.wav", @"sound",
      nil];
  PFPush *push = [[PFPush alloc] init];
  [push setData:data];
  [push sendPushInBackground];
  </code></pre>
  
  <p>What am I missing with setting up ? Why am I wrong ? Is something changed in iOS 8 ?</p>