Travis ci support

Added support for continuous integration via travis-ci.org 

It basically runs all tests (at the moment only a placeholder) each time a commit happens.

This is useful for two main reasons:

- First it enables a test driven development (not at the moment as there are no unit tests)

- It allows "outside" devs to quickly understand the multiple enviroment options and setup a similar one (for example it took me a while to discover that an error I had was do to the wrong version of django. now the information is at .travis.yml)

It is also a quick way of checking if anyone forgot to add a file to the git repo (which happens a lot) 

If you accept the pull request, then do not forget to go to travis-ci.org and enable CI for this project and update image link added to README.md to the new url.

Cheers