Cycle through extra editor windows when cycling through splits

Change-Id: I1bd5654d62b11456c35cc5bf1099e41fb3559bc7
Reviewed-by: David Schulz <david.schulz@digia.com>
Doc: hiding the mode selector

Change-Id: I1002916cc0281396ad1a7ca6481a69eeb9b58622
Reviewed-by: Eike Ziller <eike.ziller@digia.com>