Use cookiecutter (https://git.openstack.org/openstack-dev/cookiecutter)
to generate config for tox so we can generate docs, run pep8, etc.
Also move CONTRIBUTING.rst to the root of the repository in keeping
with what seems to be the standard location. This move allows us to
easily generate the docs. Also include a tiny fix to allow pep8 to
run cleanly.
Change-Id: Ifbfc6d85c7b02bf4ab989974b491a3a1ae6f0900