Can't access notification data when the app is in background or killed

Hi!

First of all, great work with this library!

```
react-native@0.48.0
react-native-fcm@10.0.2
OS: Android - Emulator - 7.0.2
```

When my app is in foreground, its working perfectly, I receive the data in this function

`FCM.on(FCMEvent.Notification, async (notif) => {`

And I can handle everything


But when the app is in background, the notification is received, but when I tap the banner, the app goes foreground, the same function is triggered, but the notif object is different, and don't contains my data.


When the app is killed, also the notification is received, but when I tap the banner, the app starts, the
`FCM.getInitialNotification()`
is triggered, and my notif object doen't also contain the data, the same behaviour than in background


I am testing the format of the messages using node-gcm library, of firebase web interface, but nothing works.

This is a sample of my message:

```
let message = new gcm.Message({
priority: 'high',
content_available: true,
timeToLive: 3,
data: {
key1: 'message1',
key2: 'message2'
},
notification: {
title: "Hello, World",
icon: "ic_launcher",
body: "This is a notification that will be displayed if your app is in the background."
},
custom_notification: {
key1: 'message1',
key2: 'message2'
}

});
```

How should I proceed to send and receive data in those cases? Because is driving me crazy.

If you need more data, ask for it :)

Thanks!!

EDIT:

I have two activities in my native part, as I am handling a splash screen in the native way. can this be causing this effect?

This is my manifest.xml. I don't want to handle local notifications, only remotes

```

```