Also added some dist_clean dirs to remove and info on using coverage.

Fixed a number of pylint issues - many more to go.  Have to balance
pylint's config with the default Google style conventions.

Info on how to use tox.  Well, just telling people to run tox, not a
huge amount of info there.

Now using reStructuredText. Cleaned up a few text errors.  Added link to
travis test status.