title: didRegisterForRemoteNotificationsWithDeviceToken doesn't return deviceToken
body: <p>I am registering for push notifications through Parse this way:</p>
  
  <pre><code>func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -&gt; Bool {
      Parse.setApplicationId("RfSGbVes0FGIX1sfxTEb3iybVsKgKPrfDuxco3vC", clientKey: "3pFBMar6vO6iUJouqTMt4VJVKZaXUc6p9RgHzTep")
      if application.applicationState != UIApplicationState.Background {
          let preBackgroundPush = !application.respondsToSelector("backgroundRefreshStatus")
          let oldPushHandlerOnly = !self.respondsToSelector("application:didReceiveRemoteNotification:fetchCompletionHandler:")
          var pushPayload = false
          if let options = launchOptions {
              pushPayload = options[UIApplicationLaunchOptionsRemoteNotificationKey] != nil
          }
          if (preBackgroundPush || oldPushHandlerOnly || pushPayload) {
              PFAnalytics.trackAppOpenedWithLaunchOptionsInBackground(launchOptions, block: nil)
          }
      }
      let userNotificationTypes = UIUserNotificationType.Alert | UIUserNotificationType.Badge | UIUserNotificationType.Sound
      let settings = UIUserNotificationSettings(forTypes: userNotificationTypes, categories: nil)
      application.registerUserNotificationSettings(settings)
      application.registerForRemoteNotifications()
      return true
  }
  
  func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
      let installation = PFInstallation.currentInstallation()
      installation.badge = 0
      println(installation.deviceToken) //deviceToken is nil
      let standardUserDefaults = NSUserDefaults.standardUserDefaults()
      standardUserDefaults.setObject(installation.deviceToken, forKey: "parseDeviceToken")
      standardUserDefaults.synchronize()
      delegate?.didFinishSettingToken()
      installation.setDeviceTokenFromData(deviceToken)
      installation.saveInBackgroundWithBlock(nil)
  }
  </code></pre>
  
  <p>When I run application I have a nil value from <code>println(installation.deviceToken)</code></p>
  
  <p>Maybe there is other way to handle <code>deviceToken</code>?</p>
  
  <p>EDIT: If I stop application and run it again, it gives deviceToken. I don't receive <code>deviceToken</code> only when I run application first time.</p>