refactor the fix for duplicate pachinko transfers

My goal here is to provide a consistent implementation of the several payday loops.

 - Add a `for_payday` parameter to `get_current_takes`, on the pattern of `Participant.get_tips_and_total`. I believe this adequately reproduces the semantics of the inline takes query currently on the `fix-payday` branch.

 - Teach `genparticipants` about the different loops, harmonizing the semantics of that generator in the various loop cases. Now it knits in different extra info based on the loop: `tips` and `total` for `payin`/`payout`, `takes` for `pachinko`.