Wrote possible fix for issue #50 (Composite command tries to remove non-existent element)

racevisionGame/src/main/java/mock/model/commandFactory/CompositeCommand.java

@@ -1,7 +1,7 @@
 package mock.model.commandFactory;
 
-import java.util.ArrayDeque;
 import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedDeque;
 
 /**
  * Wraps multiple commands into a composite to execute queued commands during a frame.
@@ -10,15 +10,15 @@ public class CompositeCommand implements Command {
     private Queue<Command> commands;
 
     public CompositeCommand() {
-        this.commands = new ArrayDeque<>();
+        this.commands = new ConcurrentLinkedDeque<>();
     }
 
     public void addCommand(Command command) {
-        commands.add(command);
+        commands.offer(command);
     }
 
     @Override
     public void execute() {
-        while(!commands.isEmpty()) commands.remove().execute();
+        while(commands.peek() != null) commands.poll().execute();
     }
 }