#68 runtests.sh needs documentation

[David D. Riddle]

There is no documentation that I can find on how to run the tests in runtests.sh. Through trial and error I have been able to run them. I would propose you add some documentation for running the unit tests. I have taken notes on how to run the tests. I included a README with instructions on how to setup and run runtests.sh.

[Michael Ströder]

automatic testing was refactored in 2.4.36+:
- python setup.py test works
- tox.ini was added