Began keyboard dev for 3.0

[Teika Kazura <teika lavabit com>]

Hi. I already began keyboard developments for Sawfish 3.0. It needs to
support xkb extension, which is described in XKBlib.pdf .  It's at
least necessary to bust the symptom caused by keyboard group switching
(because the group is in xkb extension), but some issues raised by
Chris may need it, too.

Things I know so far:
* xkb functions are included in Xlib. When xkb is present in the
  server, then some functions are replaced with xkb-extended versions.
  But there're Xkb specific functions, and we need them, too.
* header: <X11/XKBlib.h> is all.
* init: XkbQueryExtension

Openbox and metacity support xkb, but not fvwm.

Currently reading Sawfish code, X event doc, and xkb doc.

Regards,
Teika (Teika kazura)