Implements protocol message JOINING on frontend, so client in a room always displays correct room name, even when room name changes. Fixes
issue #522.
Removed in-lineedit labels such as "search:" and "room name:" due to size issues with localization and platform differences.
Send JOINING message in response to FOLLOW. Actual join may still fail due to room restrictions. Not tested.
Also convert teams to complete game config.
The whole feature is still untested at all.