add "short_location" for tweets

[Psycojoker]

Currently, locations are a big mess, from nothing to $town to $full_adress_with_lots_of_details. That's not very cool and especially not usable.

What would be cool would be a short location that would be the current town or something short enough to be tweetable.

A first simple but not perfect approach would be to default events of every organisation to a town/neighbourhood then to have a regex -> simple location table to handle most of the other cases. A best effort approach sound good, for a better result I think that we can contact organisations.

Next step would be something putable on a map (but that's probably another card).

[Psycojoker]

Fixed another way.