fix some pep8 errors that were reported as a result
nosetests are no longer maintained, updating to pytest
dropping --use-mirror from pip install as it's no longer supported (commit shared with #12 that does the same thing so I can get the travis-ci builds to work).
--use-mirrorfrompip installas it's no longer supported (commit shared with #12 that does the same thing so I can get the travis-ci builds to work).