[UI] changing chat layout will now apply on the fly

Change-Id: I5241e4bf1a89d66aea2ebed02dc01fff38ad4637
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1910
Tested-by: Jenkins CI
Reviewed-by: Damla Durmaz <ddurmaz88@gmail.com>
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>