Guild PQ + fixed negative EXP error

Implemented Guild PQ. Fixed a problem introduced earlier where negative
EXP would be deemed as "integer overflow", provoking many game breaking
issues as result.

src/net/server/world/MaplePartyCharacter.java

@@ -111,6 +111,10 @@ public class MaplePartyCharacter {
     public int getJobId() {
         return jobid;
     }
+    
+    public int getGuildId() {
+        return character.getGuildId();
+    }
 
     public void updateDoor(MapleDoor door) {
     	this.door.add(door);