Fix some concurrent mod issues

src/main/java/noppes/npcs/client/gui/mainmenu/GuiNpcAdvanced.java

@@ -163,6 +163,4 @@ public class GuiNpcAdvanced extends GuiNPCInterface2 implements IGuiData {
             hasChanges = false;
         }
     }
-
-
 }

src/main/java/noppes/npcs/controllers/data/action/Action.java

@@ -163,16 +163,28 @@ public class Action implements IAction {
 
     @Override
     public IAction getNext() {
-        int idx = manager.getIndex(this);
-        LinkedList<IAction> list = (LinkedList<IAction>) manager.getActionQueue();
-        return (idx >= 0 && idx + 1 < list.size()) ? list.get(idx + 1) : null;
+        boolean seenMe = false;
+        for (IAction a : manager.getActionQueue()) {
+            if (seenMe) {
+                return a;
+            }
+            if (a == this) {
+                seenMe = true;
+            }
+        }
+        return null;
     }
 
     @Override
     public IAction getPrevious() {
-        int idx = manager.getIndex(this);
-        LinkedList<IAction> list = (LinkedList<IAction>) manager.getActionQueue();
-        return (idx > 0) ? list.get(idx - 1) : null;
+        IAction prev = null;
+        for (IAction a : manager.getActionQueue()) {
+            if (a == this) {
+                return prev;
+            }
+            prev = a;
+        }
+        return null;
     }
 
     @Override

src/main/java/noppes/npcs/scripted/ScriptedActionManager.java

@@ -10,6 +10,7 @@ import noppes.npcs.controllers.data.action.ConditionalAction;
 import noppes.npcs.controllers.data.action.ParallelActionChain;
 
 import java.util.*;
+import java.util.concurrent.ConcurrentLinkedDeque;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -24,9 +25,9 @@ import java.util.function.Supplier;
 public class ScriptedActionManager implements IActionManager {
     private boolean isWorking = false;
 
-    private final Deque<IAction> actionQueue = new LinkedList<>();
-    private final List<IAction> parallelActions = new LinkedList<>();
-    private final List<IConditionalAction> conditionalActions = new LinkedList<>();
+    private final Deque<IAction> actionQueue = new ConcurrentLinkedDeque<>();
+    private final Deque<IAction> parallelActions = new ConcurrentLinkedDeque<>();
+    private final Deque<IConditionalAction> conditionalActions = new ConcurrentLinkedDeque<>();
 
     @Override
     public IAction create(String name) {
@@ -111,19 +112,28 @@ public class ScriptedActionManager implements IActionManager {
 
     @Override
     public IAction scheduleActionAt(int index, IAction action) {
-        if (index < 0 || index > actionQueue.size()) {
+        int size = actionQueue.size();
+        if (index <= 0) {
+            actionQueue.addFirst(action);
+        } else if (index >= size) {
             actionQueue.addLast(action);
         } else {
-            ((LinkedList<IAction>) actionQueue).add(index, action);
+            List<IAction> tmp = new ArrayList<>(actionQueue);
+            tmp.add(index, action);
+            actionQueue.clear();
+            actionQueue.addAll(tmp);
         }
-
         return action;
     }
 
     @Override
     public int getIndex(IAction action) {
-        if (action == null) return -1;
-        return ((LinkedList<IAction>) actionQueue).indexOf(action);
+        int i = 0;
+        for (IAction a : actionQueue) {
+            if (a.equals(action)) return i;
+            i++;
+        }
+        return -1;
     }
 
     @Override
@@ -200,7 +210,7 @@ public class ScriptedActionManager implements IActionManager {
 
     @Override
     public List<IConditionalAction> getConditionalActions() {
-        return conditionalActions;
+        return new ArrayList<>(conditionalActions);
     }
 
     @Override