travis-ci: Add support for running test with Travis CI

This configuration file tells Travis CI how to run our
unittests with tox in a number of different environments.
This is useful for allowing us to show our build status
on the project page and ensure community-contributed
changes do not break the build.
travis-ci: add support for sending coverage to coveralls
Merge pull request #1 from Etherios/travis-ci-support

Add Travis CI and Coveralls Support