Added CURLOPT_TRANSFER_ENCODING as the option to set to request Transfer
Encoding in HTTP requests (if built zlib enabled). I also renamed
CURLOPT_ENCODING to CURLOPT_ACCEPT_ENCODING (while keeping the old name
around) to reduce the confusion when we have to encoding options for
HTTP.
--tr-encoding is now the new command line option for curl to request
this, and thus I updated the test cases accordingly.
When TE: is inserted in the request, we must add a "Connection: TE" as
well to be HTTP 1.1 compliant. If a custom Connection: header is passed
in, we must use that and only append TE to it. Test case 1125 verifies
TE: + custom Connection:.
Transfer-Encoding differs from Content-Encoding in a few subtle ways,
but primarily it concerns the transfer only and not the content so when
discovered to be compressed we know we have to uncompress it. There will
only arrive compressed transfers in a response after we have requested
them with the appropriate TE: header.
Test case 1122 and 1123 verify.
