matplotlib Code

Fixing Qt/Qt4 blit shearing problem

Removing duplicate code from a faulty merge.

Merged revisions 4947-4950,4952-4988 via svnmerge from
https://matplotlib.svn.sourceforge.net/svnroot/matplotlib/branches/v0_91_maint

........
r4948 | jrevans | 2008-02-08 12:56:12 -0500 (Fri, 08 Feb 2008) | 2 lines

Removed a reference to nx, replaced with numpy.
........
r4977 | jdh2358 | 2008-02-19 10:26:56 -0500 (Tue, 19 Feb 2008) | 2 lines

added rec_groupby and rec2txt
........
r4987 | mdboom | 2008-02-25 15:21:39 -0500 (Mon, 25 Feb 2008) | 2 lines

[ 1901410 ] Newbie bug report: clip_on set to False actually True
........

Fix memory reservation for curve to line segment conversion.

Formatting and minor efficiency improvement.

Remove case-sensitivity for backend selection. (Not a user-visible problem)

Fix memory leak in Gtk backend.

Fix memory leaks and uninitialized memory errors discovered with valgrind.

Add valgrind memcheck support to backend_driver.py

Don't cache many-sided unit regular polygons -- just the small ones --
otherwise we could end up caching many large things.