[merge request] RandR compeltion, doc.

[Teika Kazura <teika lavabit com>]

Hi, please merge my branch.
* It completes the last RandR edit. At least it's correct if you have
  only one screen, or if you use Xinerama. Doc is done, too.
* Docs.

It has to be tested, but I think we can release 1.6.3, and no blocker
remains.

Keyboard group switching problem may be fixed soon. It'll be a minor
fix using only bit mask, and no other keyboard problem fixes won't be
included.

With best regards,
Teika (Teika kazura)