bug1: category/index.html Everytime when deleting a tag / category,
      this will be cache left on the server and would compile to html.
      we can use '$ hexo clean' to deal with it but it will purge the 'sychoo'
      directory. So be careful. 

warning1: Some of the files under this directory are not compilable 
  	  from hexo directory, so please do not delete the following 
	  files and directories:
	  bio | photos | resumes | img | test | wilkes | tmp | timeline | robots.txt | README | 404.html