Fix AirShip-Testarena startup

SpigotCore_Main/src/de/steamwar/core/events/WorldLoadEvent.java

@@ -8,6 +8,7 @@ public class WorldLoadEvent implements Listener {
 
     @EventHandler
     public void onWorldInit(WorldInitEvent e){
+        if(Integer.parseInt(System.getProperty("fightID", "0")) != -1)  // On testarenas not
             e.getWorld().setKeepSpawnInMemory(false);
     }
 }