[IMP][TEST] event: auto confirmation option, allowing to
automatically confirm events. In a simple flow it is usefull to automatically
confirm event and registrations.

[TEST] event: moved draft2done test into a unittest, easier to finely tune
in order to test the auto confirm option. Moreover this gives a basis to
further add python tests in the module. Hooray.
[IMP] event: refactored event form view. Usability reviews
showed that the form view was complicated and difficult to use. Now
that stat button and edition options in the front-end exist, it is
possible to remove some of the numerous tabs as well as some options
from the form view.

Coming: further cleaning of the model, behavior and probably the various
event-related views.