Tox based jobs for EventLogging

Creates jobs:

    mwext-EventLogging-tox-flake8
    mwext-EventLogging-tox-py27

That makes the pyflakes and pep8 jobs obsolete, and we now run tests!

Change-Id: Id9eb8f1e32f1c19b3faa9fc84fa36ee405bf1e1f