matplotlib Code

Creating branch of trunk to do some mathtext improvements

reverted some broken test code

fixed a distance bug in arrow

Fix segfault in Tk backend.

issue informative warning when calling legend() without labelled objects.

added configurable option legend.loc

Bugfixes in mlab.py to coerce inputs into numpy arrays.

In text, linespace-related changes

Minor efficiency improvements (build lists and join, rather than
concatenating strings)

Added recent tasks to the CHANGELOG.