Add Travis CI to domify

This PR adds Travis CI to domify. 

Every push and PR will automatically run on Saucelabs, testing on the current browsers, previous version, and previous previous version. Some of the browsers are not available, but will hopefully be soon.

@visionmedia right now we're using free cloudup credentials on saucelabs (the `secure` bit), but maybe we can consolidate our accounts. I think i remember you saying you had a free one for component.

Note: domify's tests currently do not pass IE9.