Add support for cancelAllLocalNotifications

Summary: Closes https://github.com/facebook/react-native/pull/2980

Reviewed By: svcscm

Differential Revision: D2550080

Pulled By: javache

fb-gh-sync-id: 76a7088f4f86191b02e6c176e4a8a7bc85f90835

Libraries/PushNotificationIOS/PushNotificationIOS.js

@@ -82,6 +82,13 @@ class PushNotificationIOS {
     RCTPushNotificationManager.scheduleLocalNotification(details);
   }
 
+  /**
+   * Cancels all scheduled localNotifications
+   */
+  static cancelAllLocalNotifications() {
+    RCTPushNotificationManager.cancelAllLocalNotifications();
+  }
+
   /**
    * Sets the badge number for the app icon on the home screen
    */