Implementation for remaining DatabaseReference methods

[Lootwig]

Are there any plans to implement onValue and get? They currently return null.

[kencana16]

also for push()

[SamuMazzi]

Also update

[jja08111]

Any updates?

[sitatec]

I will implement them as soon as I get some free time.
Pull Request are also welcome ;)

[Zohenn]

If anyone is interested, over the past couple of months I have contributed my implementation of push, get, update and remove methods.

[Markus25021975]

I'm using a FirebaseAnimatedList. When setting its query to MockFirebaseDatabase.instance.ref().child('users') I got the following error: type 'Null' is not a subtype of type 'Stream DatabaseEvent'.
This seems to be because of the missing implementations of onChildAdded, onChildRemoved, onChildChanged, onChildMoved. Is this correct? And if so, are there any plans to implement them?

[Simsen3142]

It would also be nice to have runTransaction included

[lockieRichter]

Also please add orderByChild and equalTo