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Bug fixes:
- Keep the rrule UNTIL property UTC specifier, if defined.
[mamico] (30-2)
- Set the rrule's EXDATE to the same time as the event's start time.
In our implementation we want the rrule's EXDATE property to have the same time as the event's start time.
Otherwise recurrence dates might be included where they should not due to an user-undefined EXDATE time.
[mamico] (30)