test, adapt regression cases
major, swap DT_MIRACLEDAY and DT_SUNDAY
major, migrate ywd guts to new DT_SUNDAY value
major, migrate ymd guts to new DT_SUNDAY value
major, migrate yd guts to new DT_SUNDAY value
major, migrate daisy guts to new DT_SUNDAY value
hygiene, factor our year getter for ywd->gregorians, __ywd_get_year()
major, migrate ymcw guts to new DT_SUNDAY value
chore, explicitly declaim the day-of-week for week count convention
chore, change signature of __yd_get_wcnt()
major, migrate bizda guts to new DT_SUNDAY value
Revert "test, adapt regression cases", partially

This reverts commit e09f1ba0d3ab8d8a028129a9a913d0b501fb057c.

We have to go back to %w meaning day-of-week with 0 == SUNDAY,
1 == MONDAY, etc.
major, let %w's Sunday be 00 again (like documented and like in date(1))
test, provide regression case for daisy->ywd and daisy->ymcw formatting
fix, obey DT_SUNDAY==7U directive in daisy->ywd converter
Merge branch 'feat/DT_SUNDAY==7U'

* feat/DT_SUNDAY==7U:
  fix, obey DT_SUNDAY==7U directive in daisy->ywd converter
  test, provide regression case for daisy->ywd and daisy->ymcw formatting
  major, let %w's Sunday be 00 again (like documented and like in date(1))
  Revert "test, adapt regression cases", partially
  major, migrate bizda guts to new DT_SUNDAY value
  chore, change signature of __yd_get_wcnt()
  chore, explicitly declaim the day-of-week for week count convention
  major, migrate ymcw guts to new DT_SUNDAY value
  hygiene, factor our year getter for ywd->gregorians, __ywd_get_year()
  major, migrate daisy guts to new DT_SUNDAY value
  major, migrate yd guts to new DT_SUNDAY value
  major, migrate ymd guts to new DT_SUNDAY value
  major, migrate ywd guts to new DT_SUNDAY value
  major, swap DT_MIRACLEDAY and DT_SUNDAY
  test, adapt regression cases