matplotlib Code

added cm and collections to api reference

reworked callback api for cm.ScalarMappable

changed numpy abbrev from npy to np

Updated the importation of numpy.ma; numerix.npyma is obsolete.

Change tabs to spaces, except in pyparsing.py

Fixing display of float images.

Import numpy.

Let to_rgba return uint8; track changes to cmap

Images require rgba as 4 uint8s, so it is more efficient
to generate these directly in to_rgba than to generate 4
doubles and convert them later.

The tracking of changes in ScalarMappable was handling
communication between objects, but was not keeping track of
when to_rgba needs to be rerun. A dictionary was added
to do this.

ScalarMappable.to_rgba can return uint8 instead of float64

added glen's Fc specteal patch