Update testing process to follow kotti + bootstrap upgrades

We need to use the user/browser marker + fixtures.

* Update the setup.cfg to declare them
* Use kotti testing plugin (conftest.py)
* Use Marker + fixture in tests in place of the outdated browser login method
Merge pull request #7 from majerteam/fix_upstream_tests

Update testing process to follow kotti + bootstrap upgrades
Add a MANIFEST.in for static resources inclusion

Allow to python setup.py install kotti_calendar