Update of topical areas on master should be reflected in instances

- create recurring event
- check instances' topical area
- change topical area in master 0 instances should change also
- change description in one instance to create an override
- change topical area in instance - should have no effect (should probably warn rather than ignore)
- chnage topical area in master - will be reflected in non-overridden instances - but not in override.