matplotlib Code

Improve horizontal lines in mathtext in Agg backend.

Fix bug with SVG non-math text

Fix bug with PDF non-math text

Improve font rendering considerably using a vertical hinting hack.
Hinting is disabled for all of the "vector" backends, to correct
spacing problems.

Reverting last change since it breaks on gcc-4.2

Attempting to reduce compiler warnings for gcc-4.2 (which I don't
have, but Darren Dale has reported some new warnings).

Merging mathtext changes into trunk.

Improve performance of inner loop and prevent segfaults with negative x or y in draw_bitmap.

First pass of Type 3 font subsetting for Postscript backend. Made
ttconv code exception and threadsafe. Added subsetting.

Changed ft2font.get_charmap so that it now returns a character code->glyph index dict, instead of the reverse as it used to return; updated all the files where get_charmap is used