Add an initial pylint plugin which tries it's best to enforce Py3 compatible code
Allow passing some of the modernize functions to the plugin
Options are not 'modernize' prefixed and not 'py3modernize'

Added all other options which have any meaning to this approach.
Use W1699 as the warning to trigger since PyLint's python 3 uses the
16xx range, and using the last int on that range reduces any possible
future clashes.
Issue a warning and don't register the plugin if the required libs are not available
Issue a RuntimeWarning instead of trying to log
Merge pull request #26 from saltstack/features/salt-modernize

PyLint plugin mimmicing python-modernize