Made it possible to add rooms to db and show them in app.
Changed integrity-check on createRoom.
Change in 'add_room'-icon: bigger plus-sign.
Changed the add-room-icon again. even thicker.
Deleted buttons at top and made the list fill the activity.
Cleanup after removing old buttons and acced onclickfunctions to list-items
Nicer removal of rooms (list is updated on the go)