Fix: Config: Honor configOverrides.isSoldOut

If configOverrides.isSoldOut evaluated to false,
it was ignored by the config code. So, use a
function instead to get the desired value.
Config: is housing waitlist active

As the event approaches, we need to put people
on a housing waitlist as places to stay become
scarce.
RSVP: Allow shirts to be selected
Config: Follows sold out?

If too many follows have registered, which
can sometimes happen at dance events, now we
have a flag that adjusts the RSVP page
appropriately.
Use 2014 dates