The following is a list of the response codes for the various states of
the server. Currently I would recommend we stick to the HTTP/1.0 return
codes for our errors. Once we start to support the distinction between
HTTP/1.0 and HTTP/1.1 requests from the client, then we can use the
HTTP/1.1 responses.
	-- rjkaes

[ Taken from Apache: The Definitive Guide by Ben Laurie & Peter Laurie.
  Published by O'Reilly & Associates, Inc. pg. 146-147 ]

HTTP/1.0
200	OK
302	Found
304	Not Modified
400	Bad Request
401	Unauthorized
403	Forbidden
404	Not Found
500	Server error
501	Not Implemented
502	Bad Gateway
503	Out of resources

HTTP/1.1
100	Continue
101	Switching Protocols
200	Ok
201	Created
202	Accepted
203	Non-Authoritative Information
204	No Content
205	Reset Content
206	Partial Content
300	Multiple Choices
301	Moved Permanently
302	Moved Temporarily
303	See Other
304	Not Modified
305	Use Proxy
400	Bad Request
401	Unauthorized
402	Payment Required
403	Forbidden
404	Not Found
405	Method Not Allowed
406	Not Acceptable
407	Proxy Authentication Required
408	Request Time-out
409	Conflict
410	Gone
411	Length Required
412	Precondition Failed
413	Request Entity Too Large
414	Request-URI Too Large
415	Unsupported Media Type
500	Internal Server Error
501	Not Implemented
502	Bad Gateway
503	Service Unavailable
504	Gateway Time-out
505	HTTP Version not supported