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.
* Reformat calendar plugin to ikiwiki conventions.
* The calendar plugin made *every* page depend on every other page,
which seemed a wee tiny little bit overkill. Fixed the dependency
calculations (I hope.)
* Removed manual ctime statting code, and just have the calendar plugin use
%pagectime.