Fix message composer crashes

Fix/1.0.16 fixes

Disable autocomplete for mentions if no suggestion is found and check nulls before replacing on completion

Update Stetho version/build configuration.

Sets up the debug and release buildType.

Fixes message history randomly missing from room

Updating presence status to offline instead of removing the user from Realm, whenever server sends a removed message for a user

Spotlight changes.

Removed keep-alive task and fixed the login and sign-up

 Spotlight: search for users.
Closes #321