Reimporting from quest doesn't delete old calendar events.

[ArshanKhanifar]

I've updated my lab section on quest, and now I want to get a calendar generated from my new schedule, but it also contains everything from my old calendar. Please:

• Either add an option to remove all the current calendar events.
• Or have the reimport button replace all the old events with the new ones.

[johnaoss]

Potentially similar to issue #312

[zahin-mohammad]

I have a similar issue in which after re-importing a new schedule, it'll export the old schedule.
I.e if the old schedule had a lab 201, and I reimport with a lab 204, it'll still export a lab 201.