Delete future instances of a recurring event

[willjp]

I didn't see this in the tracker so I thought I'd put it up. We can currently delete an event's entire history, or a single event from a recurring event. It would be neat if we could preserve existing history of events, but delete all future events.

I think this could be implemented by adding UNTIL to the RRULE.

[WhyNotHugo]

Sounds reasonable.

[geier]

If anybody wants to have a go at this, have a look at how and where delete_instance gets used. Delete to future could probably be done pretty analogous.