Integrate with Travis and Coveralls

[Travis CI](https://travis-ci.org/) is a continuous integration service that is free for open source projects. [Coveralls](https://coveralls.io/) is a test coverage tracking service that is also free for open source projects. This pull request adds support for integrating with these two services.

The pull request also disables the tests for the Google Translate module, which appears to be broken based on my testing. I have disabled those tests in a separate commit, so I can easily remove that commit from this pull request if the commit turns out to be working.

This should address https://github.com/embolalia/willie/issues/371.