Fixes #134 and #28

[jwiesmann]

Using keyRef.updateChildren instead of keyRef.setValue also fixes a huge amount of unnecessary 'onDataExited(DataSnapshot dataSnapshot)' events, which has not been reported yet. keyRef.updateChildren understands if the data needs to be inserted or updated. No need to use setValue here. Since priorities are not relevant anymore (https://stackoverflow.com/questions/31577915/what-does-priority-mean-in-firebase) i decided to not consider them anymore.

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[jwiesmann]

I signed it!

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[jwiesmann]

lets try again :D

[jwiesmann]

..

[samtstern]

Can you explain your decision to move to Async here?

[jwiesmann]

It looks like, that the firebase developer changed the name of that function if you do not add a CompletionListener. Before you could call setValue without listener, now you have to call setValueAsync if you do not want to use a listener. Since there is no listener required, i changed it to setValueAsync.

[jwiesmann]

Forgot to mention. I assume this is the fix for #28, since this function has been changed! (if you check some posts on stackoverflow.com, you will see that they suggest you to use a CompletionListener, which would call the 'old' function) And SetValue must have always been async

[samtstern]

@jwiesmann thanks for sending this! The core (using update) LGTM, I just want to understand your reasoning on some minor points.

[samtstern]

Also don't worry about the CLA, I manually checked and you're good to go:

[samtstern]

@hiranya911 would love your input here.

It seems like in the past, geofire was relying on the coincidence of the Android and Java RTDB SDKs having the same API surface. Then we use provided dependencies to provide the right code at runtime.

The recent Java changes break this (which is fine) but I wonder how we should proceed here. Should we lock geofire into the 5.x version of the Admin SDK forever?