A plugin to generate calendars using [pal](http://palcal.sourceforge.net/).

Main issues:

* pal's HTML output is not valid (fixed in pal SVN)
* make sure it's secure
* calendars change with time, so ikiwiki would need to be run from cron
  daily to update them, and the plugin would need to somehow mark the page as
  needing a rebuild after time had passed.  Similar to [[plugins/aggregate]].
