[Xcb] Latest changes to xcb/util sources

[Barton C Massey]

So, I've done some more changes to my util repo:

  * Moved directory util/convenient to util/aux; the old
    name is no longer sensible.
  
  * Added Doxygen comments for all of
    util/image/xcb_image.h.

  * Added a fast inline bit operations header
    util/aux/xcb_bitops.h, and documented it with
    Doxygen.

  * Added fastpath inline put_pixel and get_pixel functions
    for common cases in image/xcb_pixel.h and documented
    them a bit.
    
The only remaining plans I have are to document some
outstanding issues, and to do some additional speedups in
xcb_image_convert() to use Keithp's code in more cases and
to use the new fastpath functions when possible.

Because of the moving and renaming of directories and files,
you'll probably need to start with make distclean and
autogen.sh again to build.

  git://people.freedesktop.org/~bart/git/util.git

    Bart