[KMS] Party EXP Change

As far as I can tell, the Party EXP change reduces EXP gotten for everyone that isn't a bishop/AM. So, while this affects leechers, it also affects everyone else.

That I can understand, but it does curb leeching and still encourages partying because the attackers will be roughly earning solo EXP plus bonus party EXP. Well one good news is they are just one step away from eliminating leeching. No EXP awarded for when AFKed for over 5 min = win. Heck, we need PG accuracy too.