0.19  2017-03-07
- Documentation:
-- "week_start_day" parameter no longer marked "for internal use".
-- Fix "week day" examples. Pointed out by Eric Jensen and Zefram
   in a thread started by Andrew Martin in datetime@perl.org
-- Clarify that week_start_day defaults to "1mo", except for
   yearly recurrences that default to "mo". Patches by David Steinbrunner.
-- Updated contact email.

0.18  2015-11-11
- added a test; depends on DateTime::Set 0.3600

0.17  2005-08-11
- added a test and fixed a bug where the parameter to
  next($dt) had a timezone. Reported by Simon Wistow.

0.16  2005-05-12
- fix 'BYWEEK' -> 'BYWEEKNO'
- Depends on DateTime 0.27 because it uses local_rd_values(). 
  This fixes a local/UTC problem reported by Dave Rolsky.
- uses no DateTime.pm internals
- removed (undocumented) arguments 'after' and 'start'

0.15_02   2005-01-27
- allows interleaved neg/positive values; allows repeated indexes.
  Supports weird argument lists such as [ -200, -10, -10, 200, 20 ].
  Speed is slower by another 10%.

0.15_01   2005-01-26
- full overflow checking. 
  The previous version only checked for some kinds of month overflows.
  The tests run slower by about 12%.
- checks for invalid parameters, such as "monthly( months=>xx )" or
  "yearly( months=>xx, weeks=>xx )"
- added a dispatch table for "offset" calculations
- fixed and added tests for monthly( week => ...)
- modified "sort positive values first". Patch by Yitzchak Scott-Thoennes.
- refactored _setup_parameters()
- Updated pod and tests.

0.15    2005-01-19
- array-ref parameter lists are not mutated. Patch by Daisuke Maki.
- rewritten "sort positive values first" in _setup_parameters()

0.14
- requires DT::Set 0.17, because 0.16 had a bug that would break
  some tests.

0.13    2004-06-17
- a weekly recurrence with an interval behaves strangely,
  if the given dtstart is a sunday. Reported by Bridget Almas.
  Fix: _week() uses "week start day" in the calculation.

0.12    2004-05-26
- monthly recurrence at day 29 shows march-01. Reported by Bridget Almas.

0.11    2004-05-24
- using both 'interval' and 'start' parameters could cause the program
  to hang. Reported by Bridget Almas.

0.10    2004-03-17
0.0901  2004-03-09
- the recurrence functions accept infinite DateTimes, as required
  by DT::Set 0.1402

0.09  2003-10-10
- recurrences can be formatted using 
  DateTime::Format::ICal->format_recurrence().
  Some recurrences (ex: nanoseconds) are not supported by ICal format.
- added nanosecond tests

0.08  2003-10-31
- bugfix: when "interval==1" it should be processed as if there
  was no interval.  Found by Danny Rappleyea
- document "start" parameter.
- changed some operations in next/previous that were done twice.

0.07   2003-09-02
- tests pass under Perl 5.00503

0.06
- defines DateTime::Set::ICal class, in order to provide 
  ICal strings to represent recurrences (set/get_ical)

0.05   2003-05-23
- memoizes durations; makes less calls to DT::Duration->new
- 'weekly' can use 'week_start_day'

0.04   2003-05-14
- turn on warnings in tests and fix all warnings given.
- require DateTime::Set 0.06

0.03   2003-05-12
- iterates using binary tree
- parameter checking
- fixed behaviour of negative numbers (rfc2445)
   14h and -15min was: 13:45 = subtract 15 minutes
                  now: 14:45 = last 15 minutes of hour
- removed parameter 'year_type'
- 'duration' argument is obsolete
- added 'interval' parameter
- moved local parameters to a hash
- moved unit-specific subs to hash
- added year_type => 'weekly' to yearly (internal)
  default is year_type => 'monthly'.

0.02   2003-04-27
- tests month-day overflow for positive day offsets, if 'month'
  argument is specified. Skips a datetime if it is invalid.
- setup structure to allow other overflow tests.
- returns empty set for 'impossible' recurrences.
- many docs and code tweaks.  by Dave Rolsky

0.01   2003-04-21
- CPAN upload
- no longer inherits DateTime::Set

0.00_11

- added 'set' tests
- docs correction. Dave Rolsky

0.00_10

- ISA DateTime::Set
- removed as_set
- moved all accessors to DateTime::Set
- requires DT::Set 0.02

0.00_09

- new syntax
    $r = DT::E::R->monthly (
                       days => [ 4, 15, 18 ],
                       hours => [ 10, 20 ] );

0.00_08

- both previous and next work; all tests pass; more docs

0.00_07

- works with 2-D durations; looks up table in linear time (in worst case).
  That is, a 4x4 table gives 4^4 combinations but is looked up in 4*4 time.
  But it could be done in 4log4 time...

0.00_06

- works with multiple durations like
    $r = DT::E::R->monthly (
                       duration => \@durations );
- durations _must_ be pre-sorted.

0.00_05

- refactored constructor subs
- added a very rough multiple-duration structure 
  (doesn't work with mixed negative/positive durations)

0.00_03

- "duration" argument in constructors

0.00_02

- previous, closest, weekly