Fix linkage on c-ares enabled Windows static builds

Test 585 and 586 were added. Using a modified lib500.c

Fix the return type of the callback to match close() and make use of it.

Introduced the initial setup to allow closesocket callbacks by making
sure sclose() is only ever called from one place in the libcurl source
and still run all test cases fine.

Commit cbf4961b garbled the timeout handling while doing SSL
handshaking (in an attempt at fixing another bug). This puts sanity
back.

Bug: http://curl.haxx.se/mail/lib-2011-05/0167.html
Reported by: Ethan Glasser Camp

Added test 1126 and 1127 to verify curl's behaviour when If-Modified-Since
is used and a 200 is returned.

The list of test cases in Makefile.am is now sorted numerically.

Made the public headers checksrc compliant

Removed types.h (it's been unused since April 2004)

Made the root makefile do make in include by default as well, so that
TAGS and the checksrc will work better.

The protocol handler's flags field now can set that the protocol
requires a password, so that the set_userpass function doesn't have to
have the specific knowledge of which protocols that do.

Made several functions static

Made one function defined to nothing when RTSP is disabled to avoid
the #ifdefs in code.

Removed explicit rtsp.h includes

Add a 'readwrite' function to the protocol handler struct and use that
for the extra readwrite functionality RTSP needs.

Code cleanup to check less for protocols and more for the specific
relevant feature. Like if SSL is required.

No need to check for HTTP as this is now a HTTP-specific function

make it static, remove Curl_ prefix

Also, convert the BANPROXY flag into NONETWORK for the protocols
(file:// only atm) that don't work over networks.

As we now can specify all the socks proxy types with the regular --proxy
option using protocol prefix.

Using 'socks5h' as proxy protocol will make it a
CURLPROXY_SOCKS5_HOSTNAME proxy which is SOCKS5 and asking the proxy to
resolve host names. I found no "standard" protocol name for this.

Follow style of GNU layout (cp, mv ...) where options are separated with
comma: -o, --option

Order item alphabetically (by length also): -o, -O, --option

Follow style of GNU layout by moving help related options to the end:
--help, -M, --version

closepolicy has been deprecated and unused for years

The internal defaults are important info

As it is a separate option it should have a .IP title

Clarify that the '-', '.', '_' or '~' letters are also not escaped since
they shouldn't according to RFC3986 section 2.3.

This is how this function has behaved since sep 2010, commit
5df13c31.

Introduce an INIT state for the SSH state machine and set libssh2
non-blocking in that so that it is set properly before
libssh2_session_startup() is called.

Bug: http://curl.haxx.se/mail/archive-2011-05/0001.html

As the code already checks for it we can just as well make it official!

When checking for connections that are bound to a particular device we
must make sure we don't compare with a NULL pointer.

As it is already included by curlbuild.h if it exists on the platform it
was included here superfluously anyway.

Reported by: Dagobert Michelsen
Bug: http://curl.haxx.se/bug/view.cgi?id=3294509

There are systems (like NetWare) without its own gai_strerror()
function.