Add tox.ini for tox (http://tox.testrun.org/)
Add .tox to .gitignore
setup.py: Minor tweak to support installation on Python 3
Add .travis.yml for Travis CI (http://travis-ci.org/)
Added script to generate README.txt.

 * setup.py will ignore README.txt if it doesn't exist.
Bumped version to 0.150.1