Returns the date for a given day number.
date(daycount as word) as byte
Date in the 1-31 range.
year, month, weekday, daycount, hours, minutes, mincount
Day number. Base date for the day count is 1-JAN-2000 (this is day #0).
b = date(366) ' result will be 1 -- because day 366 is actually January 1st, 2001.