# improved winner prediction ratio for amateurs from 0.6956 to 0.7001
# amateur bout values = 1 independent of number of rounds or stopped
# improved init_bout_rating for new bouts, closer to stable value
# - init value = value last bout or
# - value next bout or
# - prior value, but opponent's value at most
# improved winner_above_loser
# - winner takes upset value
# - loser takes 0.9 upset value and 0.1 lower value