matplotlib Code

figlegends work now. (Phew!) Rendering quality fixes drawing
axis-aligned line segments in Agg.

Continued progress getting more examples to work. Working examples
(with TkAgg backend only) are marked in PASSED_DEMOS for the curious.

Simplified sharing axes again.
Plowing through -- making more examples work.
First pass at updating collections (LineCollection mostly works)

Progress on agg_buffer_to_array example.

Creating branch to work on transforms/projections refactoring.