resolve issue #2136

In original code, SingleplayerMenu's _playerdata is inited in __init__ and no more updates in show(), thus MP -> SP not work. However, MultiplayerMenu's _playerdata is inited every time in show(). thus gets udpated in color in SP -> MP. But SingapleplayerMenu's playername never gets saved, thus playername not updated in SP->MP. In MultiplayerMenu, playername and color gets saved everytime in close().