This plugin enables vCalendar message handling like the ones produced by
Evolution or Outlook, and handles webCal subscriptions. It provides a
personal calendar and public calendar import and export as well as
groupware features for Claws Mail, namely:
 * receiving meeting invitations (displaying, answering, planning)
 * sending meeting invitations
 * publishing your calendar(s) and/or your free/busy status, in order to
   help others plan meetings
 * subscribing to public calendars
 * retrieving the free/busy status of people, to help in planning
   meetings
 * reminding you of events in advance