Event add/edit form : get more often start and above all end values filled, for better calendar working

[agilare]

Ideas, reflections :

• for venues with usual schedule (get it from external API - where data is fresh- like Google, etc.) when adding it event, prefill their end time with this usual schedule

• after 1st submit without filling endtime, show warning asking to fill it and if user don't want he can submit again and event will be nevertheless accepted

• end-time importance different according to event category : fete, cine, theatre....

• look at other similar web applications for inspiration on how start and end time requirement is managed