[cairo] GSoC/scan converting rasteriser update

[M Joonas Pihlaja]

Hello again cairo-l,

Pushed more to the blog and the spans branch in my cairo repo.
Please review. Especially the interfaces.

http://people.freedesktop.org/~joonas/status-blog/
http://gitweb.freedesktop.org/?p=users/joonas/cairo;a=shortlog;h=spans

Overall, I guess things are going okay.  There's still some path
left to pave, mostly in the fallback logic, between filling a
path and it actually being rendered, but I'd say we're about a
week or so away from getting a cairo_fill() call to actually
doing the entire rendering with spans.

Then, finally, I can start plugging in some of the faster scan
converters. :)

Joonas