Issue #1415974 by caseyamcl: Allow $curlopts to override the options set by HttpClientCurlDelegate::curl().
Issue #1339906 by freblasty: Support multipart POST
Issue #1502052 by Laurent_: Added missing methods accepts and contentType to the HttpClientXMLFormatter class.
By Hugo Wetterberg: Parsing the response code so that we get an int instead of string.
By Hugo Wetterberg: Only attempting to clone if the response is an object.
Issue #1313374 by sandhurs: Only setting post fields when we're doing a PUSH, PUT or another request with a body.