matplotlib Code

Added Gael's backend fallback patch

Expanded delete_masked_points to handle more types of argument

Moved and modified axes_unit.py to cbook_unit.py.
At present it is only testing delete_masked_points,
which was moved from axes to cbook.

In collections draw methods, use get_facecolor and get_edgecolor.
The logic for edgecolors='face' is moved into get_edgecolor so
that it will return the color(s) that will actually be used.
Using the getters means that a derived class can override
them to add more logic to the choice of colors.

Move delete_masked_points() from axes.py to cbook.py so that it's available to more places.

Reverting clabel-related change in contour.py to 5689.
contour_demo.py was broken.

Add a new f2py example that uses F90 (it's still very simple).

Check for nan and inf in axes.delete_masked_points().

restored gtk quit on window close

Fixing bug in is_sequence_of_strings.