Wrapped nullable String returned to onNext with an Optional to avoid NPE eventually happening since RxJava 2.x does not support it

Do not truncate tables on initialize for those subscribers. By doing that way, the RealmUser tables were being deleted from Realm which was causing the message-user relationships to sink

Check if user is currently viewing any room by looking at the cache and if so, register to the selected room message stream

The ddp client was silently ignoring error callbacks. Throwing up an error in case at least a closed websocket issue arises

Remove user not found handling.

Show avatar with username initials.

Merge branch 'avatar-with-username-initials' of github.com:filipedelimabrito/Rocket.Chat.Android into avatar-with-username-initials

Update Google Play library version.

Removed repeated subscriptions to the same room when registering observers and unnecessary refresh calls to the RoomFragment to update its UI