multi_socket interfaces. The work-around for apps is to simply remove the
  easy handle once the time is up. See also:
  http://curl.haxx.se/bug/view.cgi?id=2501457

new and non-standard one

corrupted in ouputs. Another report from Anthony Bryan.

escape these letters what I think is the correct way.

  corrected spellings and more.

  there are servers "out there" that relies on the client doing this broken
  Digest authentication. Apache even comes with an option to work with such
  broken clients.

  The difference is only for URLs that contain a query-part (a '?'-letter and
  text to the right of it).

  libcurl now supports this quirk, and you enable it by setting the
  CURLAUTH_DIGEST_IE bit in the bitmask you pass to the CURLOPT_HTTPAUTH or
  CURLOPT_PROXYAUTH options. They are thus individually controlled to server
  and proxy.

*_socket_all() and *_socket() aren't used at all but only *_socket_action()
is.

calls. Added a paragraph explaining that libcurl takes care of low-level
protocol details. Made a few minor edits.

as a known-working environment.

wanted anyway

but I'm not in the mood to fight nroff right now...

  make CURLOPT_PROXYUSERPWD sort of deprecated. The primary motive for adding
  these new options is that they have no problems with the colon separator
  that the CURLOPT_PROXYUSERPWD option does.