matplotlib Code

Fix some recent reference counting bugs in ft2font.cpp (Thanks to Paul Kienzle).

Fix segfault in FT2Font::clear()

Fix over-allocation of alpha-channel buffer. (Reduces memory usage
with Agg by ~25%

Add a helpful comment.

Simplify and fix a memory leak.

Add support for arbitrary angles of rotation on mathtext in Agg
backend. Uses agg to rotate the raster of the text.

Created new file type1font.py for supporting Type 1 fonts;
quite preliminary for now. Started adding Type 1 support to
PDF backend for purposes of usetex.

Render all the fonts in each mathtext expression to a single image buffer
(memory and time savings).
Add support for getting raw image data for mathtext expressions.
Add mathtext_wx.py example showing how to put mathtext expressions
into controls.

Fix docstring

Make horizontal line drawing more consistent across all backends.
Fix but in ft2font glyph rendering for glyphs with a left offset.