Quick patch for the last commit

Fixed some bugs that appeared with the last commit. Added more info on
the event functions documentation.

scripts/event/VIPRockSpirit.js

@@ -96,6 +96,8 @@ function leftParty(eim, player) {
 
 function disbandParty(eim) {}
 
+function playerUnregistered(eim, player) {}
+
 function playerExit(eim, player) {
     eim.unregisterPlayer(player);
     player.changeMap(exitMap, exitMap.getPortal(0));