Crate glicko2

An implementation of the glicko2 rating system. It's a rating system appropriate for rating a team or player and is leveraged by many chess leagues.

To use, create a series of GameResult for each team or player in a rating period. Then, for each team or player pass their Glicko2Rating and list of GameResults to new_rating to calculate the new rating for that team or player, which can be saved in place of the old one. This process is then repeated each rating period.

Structs

GameResult	Represents a result (win, loss, or draw) over an opposing player or team.
Glicko2Rating	Represents the rating of a player or team on the Glicko2 scale.
GlickoRating	Represents the rating of a player or team on the Glicko (not Glicko2) scale.

Functions

new_rating

Calculates a new rating from an existing rating and a series of results.