Server-side Chunked Transfer Encoding

hi @daedric,

This pull-request adds chunked Transfer Encoding on the server side only. It currently doesn't allow sending of additional headers during the response, as I didn't think that would be an immediate use-case opposed to streaming just the content.

I've also removed the minor_, and major_ version members from the Response class as they were not being exposed/used in client code. I can't think of a client that would require HTTP 1.0 these days, but it would be easy to add back in if required.

Cheers
Matt