matplotlib Code

Removed the colormap data caching--it was trying to solve a non-problem.
Upon installation, the colormap data in _cm.py is compiled into _cm.pyc,
and importing that takes negligible time.

Cache the color data to reduce startup time.
Also, cmap kwargs now accept colormap names as strings.

Revert r7307 to the mathtex branch after a dicussion on the mailing list.

User-generated colormaps are handled more easily.

legend doc. update

Add first attempt at getting matplotlib to install mathtex.

Update the mathtex branch so that it is up-to-date with trunk.

Try to add merge tracking to the mathtex branch.

Add support for mathtext.default to the OS X backend. This still requires testing from a Mac user.

Speed up quiver for large numbers of arrows; key tip given by Ray Speth.