igir-dryrun.sh: read-only igir report for one platform vs given DAT(s),
prints an identified%% summary + sample of unmatched files (the scoring
step of the platform sweep).
igir-dorename.sh: igir move to canonical names in place for one platform,
with before/after manifests for reversibility and --dir-game-subdir never
to keep folders flat. Cart-safe; not for disc systems with .m3u.
