Comment 11 for bug 1476501

@artmello
I think we should do a couple of things here:
1. First implement the settings for a default calendar (https://bugs.launchpad.net/ubuntu-calendar-app/+bug/1373945)
2. When create a new event, use the default calendar
3. If the user disables the default calendar from the UI, make them select another calendar as the default before proceeding, that way there is always a default. If they try to disable the last calendar do not allow them.

This should insure that there is always a default calendar when creating events.