Extended english documentation (README.en.md)
Extended english documentation (README.en.md)

Added documentation of default language, Duoshuo and Disqus comments,
integration with Social Media as well as how to use an avatar.

iissnan/hexo-theme-next,chaoskyme/hexo-theme-next,flashlab/hexo-theme-next,mchsinx/hexo-theme-next,cragod/hexo-theme-next,geekrainy/hexo-theme-next,FluencyLiu/hexo-theme-next,chaoskyme/hexo-theme-next,zhipengyan/hexo,zhipengyan/hexo,ganyuanda/hexo-theme-next,Austaras/hexo-theme-next