Fixes sys.stderr() typos
Makes sure sys.std{out,err}.buffer exist on PY2
Makes signal warnings fatal during tests
Makes sure expected warnings are not fatal
Makes test output unbuffered
Makes sure all functests outputs are displayed
Fixes assertion style

This already behaved as intended (a string that matches the regex would
necessarily evaluate as True), but was not quite written in the most
sensible way.
Changes travis conf
Fixes logging arguments not lazy
Docstrings
PyLint
Fixes destroying vagrant dir after testing