Adding .travis.yml file

I did this work yesterday for 6.1, but gave up as, I thought 7.0, 6.1 and 6.0 branches were to be readonly on github and dev to be done on launchpad.

https://github.com/savoirfairelinux/canada/blob/b07761002554f077163d992b68384c58c57080db/.travis.yml