Use score-scaling Elo for non-duels.

Use score-scaling Elo for non-duels.

Scale S according to the real scorefactor in non-duel games.
This eliminates the effects of people switching to the winning
or losing team at the very last second. This also avoids a
"winner take all" in DM mode, where most people would lose points.

Additionally, all players are compared to everyone else, not just
those on their own team. This makes it more fair anyway - no
averages are done over the opponent team only. You now have to
perform better overall to get more points.