[r 0.0.71]
* collorg.communication.allowed_post_type
  Restict the permitted types of posts that can be added to a post.
  See script tools/communication/blog/post/allow_post_type.py
* Modifications to collorg.web.topic to allow its inheritance
* collorg.event.event.location_str
  temporary patch to set the location of an event
* collorg.util.ical.ICal
  class to generate iCalendar format from an event.