Add support for flake8 to travis and tox and remove pep8 and pyflakes

Change-Id: Ia27c43b5e8fad3558d8d830c154041f5c45218f6
Merge pull request #2 from rodis/feature/move_to_flake8

Add support for flake8 to travis and tox and remove pep8 and pyflakes
Add openstack.nose_plugin

Change-Id: I57f1f0d6b7562bbd8734998e75085a19c7aae874
Merge pull request #3 from rodis/feature/add_nose_plugin

Add openstack.nose_plugin