Fix cleverKeys.clearChannelBox to work with newer versions of Maya
Code Cleanup: Remove stray tabs.  Cleanup docs.

Updated copywrite and a few missing License headers.

Cleaned up docs a little by converting a few remaining
comments to docstrings.  Wrapped them to the correct
character lengths.
Don't use bare exception clauses.

Converted most of these to RuntimeError's. It doesn't help
much since Maya is so terrible at raising correct exceptions.