Merge pull request #15 from why404/master

rs-mkfile api updated
downloadToken
updated downloadToken pattern
Merge pull request #16 from why404/feature/download_token

downloadToken
hotfix download token
Merge pull request #17 from why404/hotfix/downloadToken

hotfix downloadToken pattern desc
rm publish/unpublish api
updated downloadToken hmac_sha1 desc
achor
Merge pull request #18 from why404/hotfix/remove_publish_api

rm publish/unpublish api
updated io api doc
Merge pull request #19 from why404/hotfix/update_io_doc

rebuilt io api doc