added return command within onOrientationDidChange to return subscriber object provided by RCTEventEmitter.addListener()
added return command within onOrientationDidChange to return subscriber object provided by RCTEventEmitter.addListener()

kkjdaniel/react-native-device-display,kosmaks/react-native-device-display,NishanthShankar/react-native-device-display,sf577/react-native-device-display,sf577/react-native-device-display