Put nosetests options in setup.cfg
Explicitly limit coverage to our package

Locally I seem to get reports about the 'xml' package
and on travis' pypy i get tons of other packages too.
Add basic setup.py script
Setup tox to run test suite against multiple pythons
Make 'setup.py test' work like nosetests

rather than doing absolutely nothing
Add MANIFEST.in so setup.py will work right