Adds a {@code PropertyChangeListener} to the listener list. The listener is registered for all properties. Thesame listener object may be added more than once, and will be called as many times as it is added. If {@code listener} is {@code null}, no exception is thrown and no action is taken.
Note: This is merely a convenience wrapper. All work is delegated to {@code PropertyChangeSupport} from {@link #getPropertyChangeSupport}.
@param listener the {@code PropertyChangeListener} to be added