Use pixman glyph API

[Søren Sandmann]

The following patch ports fb over to use a proposed new glyph cache
API for pixman 0.28.0. That API is described in this thread:

   http://lists.freedesktop.org/archives/pixman/2012-May/002009.html

and is available as a git repository here:

   http://cgit.freedesktop.org/~sandmann/pixman/log/?h=glyph3

The X server patch is also available here:

   http://cgit.freedesktop.org/~sandmann/xserver/log/?h=glyph2

I verified that the cairo test suite has the number of failures as
without the patch.


Soren