only save comparisons for files not matched
only save comparisons for files not matched

now why didn't i think of this sooner, this significantly reduce the
size of the comparison table, and thus query times:
v_ui_matching_list   : before: ~ 1.6 sec, after: ~0.8s
v_ui_matching_details: before: ~17.6 sec, after: ~1.9s

canidae/locutus,canidae/locutus,canidae/locutus