Added a new class .joy-content to the content block of all templates.
This matches other Joyous classes in having the joy- prefix.
The old .content class has been kept for backwards compatibility.
Return exception datetime_from properties
(_current_datetime_from, _future_datetime_from,
_past_datetime_from) in the local time zone (as per the documentation).
When prepopulating a cancellation keep the next date in the event’s timezone