CI框架中的配置：
http://blog.sina.com.cn/s/blog_591d7a460101c7sd.html
http://m.blog.csdn.net/blog/u012581409/40251303
http://blog.csdn.net/lihuang319/article/details/7002996
http://blog.chinaunix.net/uid/26642180/cid-172010-list-1.html
