chore: set up travis-ci

[juslee]

Require setting up of travis ci

[aviaryan]

@rafalkowalski Isn't the code incompatible with Python 3 (because of print statements). If so, it would be better to remove python 3 from .travis.yml and let's just concentrate on python 2.6 and 2.7 for now.

[aviaryan]

@juslee I have managed to get travis CI out of build error. Build is working fine now.
On the other hand, 7 tests are failing both locally and on travis cloud but that can be fixed.
Here is the log https://travis-ci.org/aviaryan/open-event-orga-server/builds/123264147
I will open a PR with the changes.