remove useless img
remove useless css
remove useless js like global.js
Merge remote-tracking branch 'qiniu/master' into remove_useless_code_from_old_docs_website
remove useless code
changelog.html
update docs.js (zendesk porta-feature -> portal)
Merge pull request #52 from SunLn/remove_useless_code_from_old_docs_website

Remove useless code from old docs website