matplotlib Code

Fix some python2.6 -3 warnings. (mainly usage of has_key)

Added an EllipseCollection class to collections.py

Improve masked array support in collections and quiver

Fix typo (iterator()->iterable()) for setting linestyles in Collection class.

Fix no-fill bug introduced in r5976

Fix RGBA arrays in collections.

Fix PolyCollection sizes kwarg docstring

Fix contains() for collections, moving common code from draw() into a function

fix for ps renderer dpi/imagedpi confusion

Add get_offsets, set_offsets to Collection (Ryan Kraus)