corelist.pl - Prefer more recent versions where many have the same delta

corelist.pl - Prefer more recent versions where many have the same delta

When adding a new section to %delta in CoreList.pm and Utils.pm if we find
several previous versions which we can take the delta from then prefer the
most recent version. This has the effect that when adding the 5.019004
section to Utils.pm we now choose 5.019003 rather than a random one of
5.019000 (or 5.019), 5.019001, 5.019002 or 5.019003.