Parsing HTTP Code according to RFC

I have encountered this error during testing mine apps communicating over HTTP.
Mine setup was Nginx + PHP 5.4.12 on Win.
On 500 response status was not parsed properly and Httpful threw an exception.

I still don't fully get how the http code parsing could work without this patch so I would appreciate if someone could **revise the proposed change.**
I can provide testing data for exception if necessary (don't have time right now).

OT: Anyhow I would expect from this library to take more simpler approach by checking for number till first space. (checking only for `500 ` instead of `500 Server Error...\n')