Stop registering linked listeners twice

ModifyCommand and WorldEditRenderer registered themselves as listener although
the SpigotLinker already does, so all their event handlers ran twice.

LobbySystem/src/de/steamwar/lobby/command/ModifyCommand.java

@@ -25,7 +25,6 @@ import de.steamwar.lobby.LobbySystem;
 import de.steamwar.lobby.listener.PlayerSpawn;
 import de.steamwar.sql.SteamwarUser;
 import de.steamwar.sql.UserPerm;
-import org.bukkit.Bukkit;
 import org.bukkit.GameMode;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
@@ -47,7 +46,6 @@ public class ModifyCommand extends SWCommand implements Listener {
 
     public ModifyCommand() {
         super("modify");
-        Bukkit.getPluginManager().registerEvents(this, LobbySystem.getInstance());
     }
 
     @Register