matplotlib Code

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

Added Barbs polygon collection (similar to Quiver) for plotting wind barbs. Added corresponding helpers to Axes and pyplot as well. (examples/pylab_examples/barb_demo.py shows it off.)

continue conversion of docstrings to restructured text

Add hexbin to one more place in boilerplate.py

Added hexbin axes method and pyplot function by Michiel de Hoon.
Tracker 1952339.

fixed an aspect=auto problem with bezier ellipse approx

Factored plotting part of pylab.py into pyplot.py

Added step plot based on patch by Manuel Metz

Removed last vestiges of old pcolor, scatter, quiver versions.

minor modernization