Summary:
When a recurring event start date does not match a recurrence pattern
(e.g. an event recurring on Fridays is created on Thursday),
we move the start date to the date of the first occurrence.
There's also a checkbox to keep the old behavior where the
start date was not modified.
Reviewers: vanmeeuwen
Reviewed By: vanmeeuwen
Differential Revision: https://git.kolab.org/D536
