matplotlib Code

Fix warnings on gcc 4.2.1

Remove an accidental printf.

Minor speed improvements in Agg backend.

Speed improvements for path simplification algorithm.

Add more debugging output to the path simplification code.

Fix memory leak in pcolor and pcolormesh. (Thanks Rob Hetland)

Bugfig for last commit. Don't do simplifications on filled paths
ever. (Until we can work out the difficulties).

Add line simplification, to cut down on the number of line segments
that need to be stroked. Affects *Agg and Gdk backends.

Fixed possible buffer overrun.

Handle NaNs in the data (on-the-fly as it's drawn).
Add a nan_test.py example to help ensure this stays working.