Add basic help system to pymoctool
Include program name in pymoctool errors
Add pymoc.util.tool to the documentation

The tool's docstrings now include some RST which has to be
stripped out by the _split_docstring method.
Mention pymoctool in the README file
Prepare version 0.3.0 release
Implement __ne__ method of MOC class

This just calls self.__eq__ and applies the not operator.

Not defining __ne__ was causing the doctests to fail when run with
Sphinx running on Python 2.  They passed with Sphinx on Python 3,
even though the Python 3 documentation also mysteriously says that
__ne__ should be defined whenever __eq__ is.