matplotlib Code

Minor fix to conversion of should_simplify.

Snapping bug in last commit.

Does simplify paths when NaN/inf is present.

Fix MPL_notisfinite64

Don't check for invalid values in get_path_extents.
It is the path iterator's responsibility to filter them out.

Check for isfinite in get_path_extents.
This is part of an experiment to make nan and inf be ignored
equally throughout plotting; it may turn out to be unnecessary,
in which case it should be reverted for the sake of efficiency.

Use MPL_notisfinite in place of MPL_isnan

Speed improvements in quadmesh. Proper ref-counting in error case.

Fix memory leaks in ttconv (that manifest themselves in the PDF and PS backends).

removed screen noise comments from gtkagg and image since I no longer consider this to be a bug