Add "score" command, which can be used by any user to view the current score of any other user (even across games).  Also allows admins to modify a user's current score, which can be useful on private servers where admins are playing and can "repair" a score if someone gets disconnected or kicked accidentally.
Merge branch 'score-cmd' of https://github.com/uecasm/PretendYoureXyzzy into uecasm-score-cmd