Impress slides backend

[Bastien Nocera <hadess hadess net>]

Heya,

In bugzilla:
http://bugzilla.gnome.org/show_bug.cgi?id=308637

You will be able to find a new backend to load Impress slides. The
rendering is far from perfect, due to the rather beta state of imposter-
ng, but G�ill be working on it soon.
There are threading issues currently that I plan on fixing using Cairo
as the drawing backend, rather than drawing on a GdkWindow.

Cheers

---
Bastien Nocera <hadess hadess net> 
"If God had wanted us to play football in the clouds, he'd have put
grass up there" - Brian Clough, on the importance of passing the ball to
feet.