Added file .travis.yml

[Travis ci] [1] is a great tool that can run test for every commit. It has a feature that is shows test result for every pull request ([img][2]). So I think it is a good idea to enable travis ci in the superb tool.

 [1]: https://travis-ci.org/
 [2]: http://upload.bessarabov.ru/bessarabov/TUbmAQqjE2jfljZxgYtTcFvhpsc.png