Merge branch 'gh-pages' of https://github.com/basestyle/grunt-cn into gh-pages

# By TooBug
# Via TooBug (3) and basecss (2)
* 'gh-pages' of https://github.com/basestyle/grunt-cn:
  添加ajax 404时的错误提示
  增加出错提示
创建任务文档修正