http: use official IANA Status Codes

* adds missing HTTP status codes
* corrects those with a wrong description
* the falsely included codes have been kept

PR-URL: https://github.com/nodejs/io.js/pull/1470


Reviewed-By: Brendan Ashworth <brendan.ashworth@me.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: James M Snell <jasnell@gmail.com>