TRadioButton class file

• version: $Id: TRadioButton.php 1453 2006-10-01 03:09:18Z wei $
• license: http://www.pradosoft.com/license/
• copyright: Copyright © 2005 PradoSoft
• link: http://www.pradosoft.com/
• author: Qiang Xue <qiang.xue@gmail.com>