* The calendar plugin stores state about when it needs to be updated,

* The calendar plugin stores state about when it needs to be updated,
  and forces rebuilds of the pages that contain calendars. So
  running ikiwiki --refresh at midnight is now enough, no need for a full
  wiki rebuild each midnight.
* calendar: Work around block html parsing bug in markdown 1.0.1 by
  enclosing the calendar in an extra div.