#295 IPL file datetimeicn : bug in procedure dayoweek

[Bruce Rennie]

The procedure dayoweek in the file datetime.icn has a bug that gives the incorrect weekday for the months of February and May. the following date examples give the wrong day

1-Feb-1901 gives the weekday of Wednesday when it should be Friday

1-May-1901 gives the weekday of Saturday when it should be Wednesday