Documentation on free-for-all

[TypicallyThomas]

Hi there. Great library!

I was reading the documentation and I feel like there's very little information on free-for-all games, especially when it comes to non-zero sum games. I'm unsure how to rate players in a non-zero sum game like racing, for example. How do you take distance from winning into account, for example? Do I just input a list of the result, normalized to between 0-1? In any case, I feel this could be clearer in the docs. Thanks!