AmoriaPQ + ItemSort fix + revamped GMShop

Implemented AmoriaPQ. Fixed an issue with ItemIdSortHandler where empty
vectors given to the sorting module would cause an exception thrown,
wiping players inventory items. Thanks to Vcoc, revamped shop data for
GMShop (shop id 1337). Mount quest for explorers now uses event script.

src/server/maps/MapleMap.java

@@ -1386,7 +1386,7 @@ public class MapleMap {
         final ScheduledFuture<?> monsterItemDrop = TimerManager.getInstance().register(new Runnable() {
             @Override
             public void run() {
-                if (MapleMap.this.getMonsterById(m.getId()) != null && !MapleMap.this.getPlayers().isEmpty()) {
+                if (m.isAlive() && !MapleMap.this.getPlayers().isEmpty()) {
                     if (item.getItemId() == 4001101) {
                         MapleMap.this.riceCakes++;
                         MapleMap.this.broadcastMessage(MaplePacketCreator.serverNotice(6, "The Moon Bunny made rice cake number " + (MapleMap.this.riceCakes)));
@@ -1395,7 +1395,7 @@ public class MapleMap {
                 }
             }
         }, delay, delay);
-        if (getMonsterById(m.getId()) == null) {
+        if (!m.isAlive()) {
             monsterItemDrop.cancel(true);
         }
     }