Update pep8 and then appease it

- E713 test for membership should be 'not in' fixed
- This alert was added in about a week ago: https://github.com/jcrocholl/pep8/blob/a176b77c22ef0c0263ca4f956b9b7c91ea659885/CHANGES.txt#L87
- Should kick off our first travis run
Merge pull request #3 from alphagov/pep-bump

Update pep8 and then appease it