package ints provides a standard Inter interface and basic functions
defined on Inter types that support core things like Max, Min, Abs.
Furthermore, fully generic slice sort and conversion methods in the kit type
kit package attempt to use this interface, before falling back on reflection.
If you have a struct that can be converted into an int64, then this is the
only way to allow it to be sorted using those generic functions, as the
reflect.Kind fallback will fail.
It also includes Max, Min, Abs for builtin int64, int32 types.