matplotlib Code

Update to use modern Numpy C API

Further speed improvements. For collections, now has faster ignoring
of elements that aren't provided, such as offsets. Paths now do not
even store the "default" codes array -- which is MOVETO followed by N
LINETOs. These are generated automatically by the iterators if no
codes array is provided. (Should also result in significant memory
savings for graphs with many points.)

Forgot to svn add these files in last commit.