Make enum keys of type EnumKey, not int #782
Description
Currently keys in Enums are all ints.
It's probably more clear to make them type EnumKey int, just for clarity. For example, GameDelegate.GroupMembership has to explain in documentation what map[int]bool means.
It's a little confusing that a given int isn't guaranteed to be in a given Enum, but at least it's clear what the intent is.