Feature Request: average APS diff in bots compare

The common %score is calculated just like APS, but only for pairings that the old and new versions have in common. That makes it easier to compare two versions when the new one is still missing many pairings, or in the case where the old bot may have pairings against a lot of retired bots (and may be missing scores vs newer bots). I think that's what you're looking for...