Changed the "im_used" informational status code for the value given by IANA (226)

See RFC 3229 at http://tools.ietf.org/html/rfc3229#section-10.4.1 and HTTP status codes at http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
Set 208 status_code to "already_reported"
Merge pull request #1456 from phndiaye/master

Changed the "im_used" informational status code for the value given by IANA (226)