public void Redo()
        {
            IUndoKomanda redoCommand = redoStack.Pop();

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