- API Refactoring in base.py:
    * get_portal_events and get_occurrences_from_brains combined to get_events.
    * get_occurrences_by_date refactored to construct_calendar.
    * BBB code will be removed with 1.0.
reorder
reorder
- Introduce create and edit functions in IEventAccessor objects.
 - In tests, use AbstractSampleDataEvents as base class for tests, which depend
  on AT or DX event content.
more unifying of AT/DX tests
use new get_events api
use assertequal instead asserttrue
test new get_events API. fix sorting of attrs in ret_mode=2 and expand=True
fix signature and test construct_calendar
adapt to new get_events API. - Remove render_cachekey from portlet_events, since it depends on an
  undocumented internal _data structure, which must contain catalog brains.
  [thet]
adapt to new get_events and construct_calendar API
  In ical:
    * Renamed construct_calendar to construct_icalendar to avoid same name as
      in base.py.
mark deprecations