Summary:
In order to add Push support to the Parse JS SDK in React Native, we need a way to receive the APNS device token from the JS context. This adds another event to PushNotificationIOS, so that code can respond to a successful registration.
Additionally, I've updated the `requestPermissions` call to accept an optional map of parameters. This way, developers can request a subset of user notification types.
Closes https://github.com/facebook/react-native/pull/1304
Github Author: Andrew Imm <andrewi@fb.com>
Test Plan: Imported from GitHub, without a `Test Plan:` line.