操作XML的类，用VC++实现的，很容易理解的代码，对初学者有用处-XML class operation with a VC++ to achieve, it is easy to understand the code, useful for beginners

xml2库源码，版本号2.9.1。以在产品上应用，目前没发现bug。(libxml2 source code, version number 2.9.1.)