[cairo] Text support for PDF backend landed

[Kristian Høgsberg]

Hi all,

I just comitted support for text to the PDF backend.  Currently it's a 
bit limited in that it only supports TrueType fonts with the freetype 
backend and only black text.  This means no red numbers when printing 
out your spreadsheets!  Also, there's an encoding problem I haven't yet 
fixed that makes Adobe Reader unhappy with the output.  The output is 
viewable in the various open source PDF viewers, though.

The bulk of the patch is for creating a TrueType file containing the 
subset of glyphs used by the PDF document from a given FT_Face.  The 
design should be able to support other font backends, but I haven't yet 
looked into that.

There is still a number of loose ends to tie up in the code, but it 
should be basically useful (as long as you don't want coloured text).

cheers,
Kristian