Updated the makefiles and Visual Studio project files to support moving
the authentication code to the new lib/vauth directory that was started
in commit 0d04e859.

Add ALPN support for schannel. This allows cURL to negotiate
HTTP/2.0 connections when built with schannel.

Closes #724

Use the local, reasonably updated, 'now' value when creating the message
string to output for the timeout condition.

Fixes #619

... so we don't need extra boringssl precautions for for
HAVE_ERR_REMOVE_THREAD_STATE_NOARG.

Pointed-out-by: David Benjamin

The removed arg is only done in OpenSSL

Bug: https://twitter.com/xtraemeat/status/712564874098917376

... and update the coming release dates a bit

Follow up to commit a8c7f0fc prior to release.

Bug: https://github.com/curl/curl/issues/685

It seems we may have some autobuild problems after this commit went
in. Trying to see if a revert helps to get them back.

This reverts commit 2716350d.

... makes it a lot faster

... to make it look nicer in markdown outputa

- Do not use wolfSSL's sample user-setting files.

wolfSSL starting in v3.9.0 has added their own sample user settings that
are applied by default, but we don't use them because we have our own
settings.

- Do not use wolfSSL's Visual Studio Unicode character setting.

wolfSSL Visual Studio projects use the Unicode character set however our
settings and options imitate mingw build which does not use the Unicode
character set. This does not appear to have any effect at the moment but
better safe than sorry.


These changes are backwards compatible with earlier versions.

warning C4189: 'data': local variable is initialized but not referenced

...and some minor formatting/spacing changes.

Support for the (undocumented) AuthorizedKeysFile2 was removed in
OpenSSH 5.9, released in September 2011

Closes #715

warning C4189: 'data': local variable is initialized but not referenced

warning C4706: assignment within conditional expression

Rather than use TRUE, FALSE, NULL, 0 or != 0 in if/while conditions.

Additionally, corrected some example code to adhere to the recommended
coding style.

warning: conversion to 'unsigned char' from 'int' may alter its value

vtls/mbedtls.h:67:36: warning: implicit declaration of function
‘mbedtls_sha256’ [-Wimplicit-function-declaration]

Following commit c5744340. Additionally removes the need for a second
'result code' variable as well.

.. because curl_multi_wait can no longer signal poll failure.

follow-up to 77e17267

Bug: https://github.com/curl/curl/issues/707

As these files don't need to contain references to the source files,
although typically do, added basic files which only include three
filters and don't require the project file generator to be modified.

These files allow the source code to be viewed in the Solution Explorer
in versions of Visual Studio from 2010 onwards in the same manner as
previous versions did rather than one large view of files.

warning C4706: assignment within conditional expression

warning C4668: 'USE_IPV6' is not defined as a preprocessor macro,
               replacing with '0' for '#if/#elif'

warning C4701: potentially uninitialized local variable 'size' used

Technically this can't happen, as the usage of 'size' is protected by
'if(parsed)' and 'parsed' is only set after 'size' has been parsed.

Anyway, lets keep the compiler happy.

Since gcc 5, the processor output can get split up on multiple lines
that made the configure script fail to figure out values from
definitions. The fix is to use cpp -P, and this fix now first checks if
cpp -P is necessary and then if cpp -P works before it uses that to
extract defined values.

Fixes #719