is now treated as an error by libcurl

with Digest or NTLM. libcurl will now use HEAD to negotiate the authentication
and when done perform the requested POST.

even with authentcations such as NTLM or Digest enabled. Test cases 150, 151
and 152 were added to verify the functionality.

CURLOPT_POSTFIELDSIZE option to allow really big HTTP POSTs.

machines.