[cairo] Finer-grained fallbacks for the PostScript backend

[Adrian Johnson]

One of the planned cairo features is finer-grained image fallbacks
for backends that use the analysis surface. I have been working on a
patch to make the PostScript backend use finer-grained fallbacks. The
patch is available here:

http://gitweb.freedesktop.org/?p=users/ajohnson/cairo.git;a=shortlog;h=finer-grained-fallback

The one remaining problem I have not been able to fix is that gradient
and surface patterns do not work with both a device scale and device
offset specified. The patch works correctly if the fallback resolution
is set to 72dpi as this results in a device scale of 1.