saberma/19wu — pull request #312 by saberma (2013-04-02 12:38:53+00:00)
Title: 增加 markdown 保留空格的说明 #295

如下图：

![markdown-pre-code](https://f.cloud.github.com/assets/15178/328199/2da844e2-9b92-11e2-9442-f1dbe3607957.png)

#295