matplotlib Code

Tweaked automatic contour level calculation

Minor cleanup of arguments and docstring in contour

axes.py: Reverted get/set xlim/ylim methods to original state
Added get/set xbound/ybound to handle axes inversion maintenance
Removed inverted axes flags
patches.py: Added some logic to xform an Ellipse angle as per the Ellipse's transformation.

Fix for "NameError: global name 'ones' is not defined"

Merged from trunk (a somewhat hairy manual merge this time). Fixed
bug (on this branch only) where inverted axes were broken.

Progress on agg_buffer_to_array example.

Sharing axes across figures is much easier now (it is the same as
within the same figure), so this demo has been updated.

Lots of new docstrings. Reasonably good state for polar plots.
r-axis labels can be dragged on polar plots. r-scale can be zoomed on
polar plot. Lots of other minor changes too numerous to mention.

Removed an erroneous print statment in backend_qt.py.
Added a feature to keep track of axes inversions.

Moved a couple of routines from the Agg version of the FigureCanvas to the base qt
version where they belong. Added a couple of overloaded qt methods that should be
there and reduce having to inherit when embedding in another QWidget.