corelist.pl - Fix the updating of %released

The code to not update %released if $perl_vnum is already in it didn't work
correctly. Fix this.
corelist.pl - Improve the updating of %delta and %deprecated

Both of these hashes needed to have the existing stub sections for the new
$perl_vnum manually removed prior to running corelist.pl otherwise a second
section for $perl_vnum got added. The script now deletes any such existing
section itself before adding the new (real) one.
corelist.pl - Correct the indentation of %delta's 'removed' entries

The indentation was only 11 characters instead of 12 to match the 'changed'
entries.
corelist.pl - Apply BinGOs's "First stab" at updating Utils.pm

This is commit bdb83d4b01.
corelist.pl - Apply BinGOs's commit "Two" at updating Utils.pm

This is commit 402e920b67.
corelist.pl - Various tidy-ups
corelist.pl - Fix make_coreutils_delta()
corelist.pl - Put the new utilities delta section in place

This includes removing any existing stub section for this $perl_vnum first.
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.
corelist.pl - Update RMG to reflect recent changes