[Gnome-print] Gnome Print RGBA

[Lauris Kaplinski <lauris ariman ee>]

Hello,

I just finished first step porting sodipodi RGBA printing to
libgnomeprint. It can be found in branch gnome-print-rgba

Main changes:
GnomePrintRBuf context
- renders into RGB or RGBA buffer.
- does not need GnomeCanvas, i.e. no X required
- buffer can be arbitrary rectangle with its own affine transformation

libart RGBA renderers (art_rgba_svp and art_rgba_rgba_affine)
These should go to libart, but until Raph has looked onto these they are
here.

GPPath object
This is replacement to GnomeCanvasBpathDef
- is always terminated with ART_END
- checks bpath integrity
- has closed flag
- can be created from static bpath
- has concat, split and copy functions

The printing context has several glitches and clipping is not yet 
implemented. But it can already produce nice bitmap images and gives
necessary functions to implement RGBA printing in PostScript context.

I would be glad, if anybody would test this out.

Lauris