Now there is a WelcomePanel in GameFrame.
WelcomePanel has a MenuPanel, AboutPanel, and HowToPanel.
MenuPanel has some change; its listeners are some changed; they are not doing smart jobs they call related method from welcomePanel.
GameFrame has WelcomePanel and GamePanel, and only cares about printing welcomePanel and gamePanel.
WelcomePanel cares about printing MenuPanel, AboutPanel, and HowToPanel.