Log Message:
Update from version 0.08 to 0.09.  Changes:

0.09     2008-03-07

- The output of format_datetime() always includes the time
  portion. Without this the module produced what I think was an
  invalid iCal date. More importantly, this makes the output
  consistent (always a DATE-TIME). Reported by Bill Moseley.

- removes RRULE: and EXRULE: from ICal string before parsing.
  Reported by Matt Sisk.