public void Undo()
        {
            IUndoKomanda undoCommand = undoStack.Pop();

            undoCommand.Vrati();
            redoStack.Push(undoCommand);
        }
        public void Redo()
        {
            IUndoKomanda redoCommand = redoStack.Pop();

            redoCommand.Izvrsi();
            undoStack.Push(redoCommand);
        }
 public void DodajIIzvrsi(IUndoKomanda novaKomanda)
 {
     novaKomanda.Izvrsi();
     undoStack.Push(novaKomanda);
     redoStack.Clear();
 }