// given year (time is set to 0), return true on success and false on
// failure. n may be positive (1..5) or negative to count from the end
// of the month (see helper function SetToLastWeekDay())
// given year (time is set to 0), return true on success and false on
// failure. n may be positive (1..5) or negative to count from the end
// of the month (see helper function SetToLastWeekDay())