Got rid of dreaded invert_originals in favour of cleaner approach
settings->keep_all_tagged => keep all duplicate instances in paths tagged with //
settings->keep_all_untagged => keep all duplicate instances in paths not tagged with //
settings->must_match_tagged => ignore duplicate sets with no member in paths tagged with //
settings->must_match_untagged => ignore duplicate sets with no member in paths NOT tagged with //
Also CAPITALISED a couple of #defines
Disallow --keep-all-tagged and --keep-all-untagged similultaneously