Update setup.py, Travis CI and added Coveralls

Don't merge yet!

I'm just updating `setup.py` with better (and more robust) support for the tests I've already written.  I noticed the the Travis-CI documentation suggests using `pip` instead of `apt-get` if at all possible and I'm still have some trouble getting this sorted out.  So please don't merge until I've done that  - and perhaps you have some suggestions?

W