Move systests into a separate maven project.

Change-Id: I66845782ec3036445b9c4e26440f99774af48cd9
Reviewed-on: http://naan.mimuw.edu.pl:8001/68
Tested-by: Nebulostore Nebulostore <nebulostore@gmail.com>
Reviewed-by: Szymon Matejczyk <smatejczyk@gmail.com>