[Xcb] XKEYBOARD protocol definition

[Peter Harris]

I'm preparing to push the GSOC protocol definition for XKEYBOARD. Please
take a look at git://anongit.freedesktop.org/~peterh/xkbproto

I currently plan to squash all the changes, both mine and Mariusz's,
into a pair of commits. One to update the docs and .xsd to allow the new
elements, and one that simply adds the final xkb.xml.

Review welcome.

My changes since the last time we discussed xkb.xml are:

 - Remove 'type' from 'sumof'
This attribute seems unnecessary.

 - Resolve name collisions in xkb
Names inside switches were colliding with names outside switches (while
still depending on the value from outside the switch).

 - List length is in list elements, not bytes
Most lists had their length calculated incorrectly.

 - Remove <if> construct; it is unnecessary
This change depends on BOOL always being xTrue (1) or xFalse (0).

 - Clean up comments

 - Improve definition of 'SetMap'
Cases where a list of CARD8 was being used instead of the appropriate
struct inside the SetMap request.

Note that I have not reviewed the GSOC changes to libxcb. These changes
only address the protocol definition.

Thanks,
 Peter Harris
-- 
               Open Text Connectivity Solutions Group
Peter Harris                    http://connectivity.opentext.com/
Research and Development        Phone: +1 905 762 6001
pharris at opentext.com            Toll Free: 1 877 359 4866