When CURL_DISABLE_CRYPTO_AUTH is defined the DIGEST-MD5 code should not
be included, regardless of whether USE__WINDOWS_SSPI is defined or not.
This is indicated by the definition of USE_HTTP_NEGOTIATE and USE_NTLM
in curl_setup.h.

* Added information regarding the February 2003 Platform SDK for VC6
* Updated the introduction to be similar to the IDE projects README

Added a more thorough version of the VC8 project files that exist in
the "vs" folder with the intention to add support for other versions of
Visual Studio. These files support side-by-side compilation, 32-bit and
64-bit builds as well as support for some of the third-party libraries
curl uses.

And clarify for curl that --proxy-header now must be used for headers
that are meant for a proxy, and they will not be included if the request
is not for a proxy.

Updated the docs to clarify and the code accordingly, with test 1528 to
verify:

When CURLHEADER_SEPARATE is set and libcurl is asked to send a request
to a proxy but it isn't CONNECT, then _both_ header lists
(CURLOPT_HTTPHEADER and CURLOPT_PROXYHEADER) will be used since the
single request is then made for both the proxy and the server.

... and sorted the list

Modified the logic so that CURLOPT_HEADEROPT now controls if PROXYHEADER
is actually used or not.

Includes docs and new test cases: 1525, 1526 and 1527

Co-written-by: Vijay Panghal

Without request body there's no point in asking for 100-continue.

Bug: http://curl.haxx.se/bug/view.cgi?id=1349
Reported-by: JimS

When doing passive FTP, the multi state function needs to extract and
use the happy eyeballs sockets to wait for to check for completion!

Bug: http://curl.haxx.se/mail/lib-2014-02/0135.html (ruined)
Reported-by: Alan

Since all present tests now have <keywords> listed, this script will now
refuse to run a given test case if no such section is provided.
Hopefully this will help us make sure new test cases get keywords added
at start.

In addition to commit fe260b75 fixed the same issue for RFC-821 based
SMTP servers and allow the credientials to be given to curl even though
they are not used with the server.

Reported-by: Melissa

Added SMTP (RFC-821 only) based test case as a reference for the fix
provided by commit fe260b75.

Follow up to 9317eced makes test 1056 work again.

This limitation was removed in commit 0bc4938e

Remove a superfluous "negotiated http2" info line

We're progressing throught drafts so there's no point in having a fixed
one in a symbol that'll survive.

This makes it possible to fetch from an IPv6 literal without specifying
the -g option.  Globbing remains available elsehwere in the URL.

For example:
  curl http://[::1]/file[1-3].txt



This creates no ambiguity, because there is no overlap between the
syntax of valid globs and valid IPv6 literals.  Globs contain hyphens
and at most 1 colon, while IPv6 literals have no hyphens, and at least 2
colons.

The peek_ipv6() parser simply whitelists a set of characters and counts
colons, because the real validation happens later on.  The character set
includes A-Z, in case someone decides to implement support for scopes
like [fe80::1%25eth0] in the future.

Signed-off-by: Paul Marks <pmarks@google.com>