some fixes

• [android] presentLocalNotification and custom_notification will not trigger a notif event when showing notification.
• fixed type definition error #473

allow deleting instanceId

#467

allow android alias activity

#449

ios warning fix

fix iOS warning on NSNumber

bug fix iOS init notification

fix init notification being empty in iOS

bug fix

fix #431

ios SDK v4

make change for SDK v4

BREAKING CHANGES:
direct channel are turned off by default in iOS now. to enable it you need to call FCM.enableDirectChannel()

other new methods for iOS
FCM.isDirectChannelEstablished()
FCM.on(FCMEvent.DirectChannelConnectionChanged, callback)
FCM.getAPNSToken()

update typescript definition

v6.2.3

Update package.json

add typescript definition

v6.2.1

Update package.json

buildToolsVersion 25

use buildToolsVersion 25 and targetSDK 25