Fix BauSystem RedstoneTester loading

Fix CommandGUI RedstoneTester loading

BauSystem_Main/src/de/steamwar/bausystem/BauSystem.java

@@ -99,7 +99,9 @@ public class BauSystem extends JavaPlugin implements Listener {
         getCommand("script").setExecutor(new CommandScript());
         getCommand("simulator").setExecutor(new CommandSimulator());
         getCommand("simulator").setTabCompleter(new CommandSimulatorTabCompleter());
-        getCommand("redstonetester").setExecutor(new CommandRedstoneTester());
+        if (Core.getVersion() >= 15) {
+            getCommand("redstonetester").setExecutor(new CommandRedstoneTester());
+        }
         getCommand("gui").setExecutor(new CommandGUI());
 
         Bukkit.getPluginManager().registerEvents(this, this);
@@ -110,7 +112,9 @@ public class BauSystem extends JavaPlugin implements Listener {
         Bukkit.getPluginManager().registerEvents(new TNTSimulatorListener(), this);
         Bukkit.getPluginManager().registerEvents(new CommandGUI(), this);
         Bukkit.getPluginManager().registerEvents(new DetonatorListener(), this);
-        Bukkit.getPluginManager().registerEvents(new RedstoneListener(), this);
+        if (Core.getVersion() >= 15) {
+            Bukkit.getPluginManager().registerEvents(new RedstoneListener(), this);
+        }
         new AFKStopper();
 
         autoShutdown = Bukkit.getScheduler().runTaskLater(this, Bukkit::shutdown, 1200);

BauSystem_Main/src/de/steamwar/bausystem/commands/CommandGUI.java

@@ -81,7 +81,11 @@ public class CommandGUI implements CommandExecutor, Listener {
             if (Welt.noPermission(player, Permission.build))
                 return;
             player.closeInventory();
-            player.performCommand("redstonetester");
+            if (Core.getVersion() >= 15) {
+                player.performCommand("redstonetester");
+            } else {
+                player.sendMessage(BauSystem.PREFIX + "Der RedstoneTester ist nicht in der 1.12 verfügbar");
+            }
         });
 
         inv.setItem(40, getMaterial("WOODEN_AXE", "WOOD_AXE"), "§eWorldedit Axt", getNoPermsLore(Arrays.asList("§8//§7wand"), player, "§cDu hast keine Worldeditrechte", Permission.worldedit), false, clickType -> {