Add support for travis-ci

Hi Jim,

This PR adds support for http://travis-ci.org to automatically build master and show the status on the main project page. I had added it to my local copy to make sure my spec failures weren't local.

The steps on the link below will need to be completed before travis-ci will work fully.

http://about.travis-ci.org/docs/user/getting-started/

Thanks!
Greg