Add setup.cfg for flake8
Make all code pep8 / flake8 compliant
Make flake8 a requirement, remove ipython
Make travis run flake8
Add instructions for installing flake8 pre-commit hook
Merge pull request #93 from OAButton/feature/pep8

Make all code pep8 / flake8 compliant

To make it stay that way, add flake8 to requirements and have travis
run flake8.

Please install the following flake8 pre-commit hook to make sure
your code complies before committing in future:

  flake8 --install-hook