Importing development code into trunk.
Implemented new scheme to pass weekday information to relativedelta.
Adding first version of the rrule module.
Many fixes.
Finished implementation of hourly, minutely and secondly support.
Reorganized parser module in classes, and renamed the tzoffsets keyword
parameter of parser() function to tzinfos.
Fixed tests to use new tzinfos keyword of parse() function.
Fixed moin documentation to use new tzinfos keyword of parser() function.
- Implemented byeaster extension.
- Exchanged the order of freq and dtstart, making dtstart an optional
  parameter. If it's not given, datetime.now() will be used.
Started documenting the rrule type.
Implemented tzical type, and fixed many bugs in rrule type.
- Implemented caching and between() method in rrule and rruleset.
- Documentation updates.
- New tzical.keys() method.
Many fixes in rrule type and updated documentation.
More fixes, speedups, and documentation.
- Implemented cross year weekly periods support.
- Minor optimizations.
Implemented new algorithm for finding relative weekdays.
Implemented new algorithm for relative weekdays.
Many new rrule tests.
Handle numbered weekday (MO(-1)) with frequencies higher than monthly
by dropping the number.