Add a chinese forum link

Many Chinese people cannot go to offical forum.
http://tieba.baidu.com/f?ie=utf-8&kw=ppsspp is best for them
When select zh_CN lanauge,will display the link.
![2](https://f.cloud.github.com/assets/2177532/1006676/014f34fe-0aec-11e3-9801-14a8143f91ba.jpg)