This program was written by Pierre-Michel THEVENY <pmth@free.fr>
with the help of Glade and Kdevelop

Conversion from Gregorian date to mofified Julian day and vice-versa are
derived from the Communications of the ACM (CACM, volume 11, number
10, October 1968, p.657) Henry F. Fliegel and Thomas C. Van Flandern
