renamed methods to better indicate what they're being used for.
ditched archivedOnly argument from _getOfferingsForCalendarFeed() and hardwired this as a constraint into the SQL query.
shedded the $year argument from _getOfferingsForCalendarFeed().
code cleanup.
made user id mandatory in calendar feed query. changed argument order around in _getOfferingsForCalendarFeed() to push the mandatory $userId to the front of the list.