Best Match w/ quality ratio merging

Best Match w/ quality ratio merging

 * Mew Best Match option in merge/overlay
 * support for upload time minimum record quality ratio
 * We now /only/ create new records if no matches exist and the user
   selected a match-free import
 * Selecting a match-free import no longer trumps other merge imports.
   They both work together now.

TODO: find out why queued record quality is not getting set at queued
rec creation time.