Make them smaller and more similar for each separate SSL library
supported by the configure build

76 private header files renamed to use our standard naming scheme.

This change affects 322 files in libcurl's source tree.

BLANK_AT_MAKETIME may be used in our Makefile.am files to blank
LIBS variable used in generated makefile at makefile processing
time. Doing this functionally prevents LIBS from being used for
all link targets in given makefile.

You can do custom commands to FTP without sending anything by using the
CURLOPT_NOBODY, which -I sets.

Blocking connect on the socket has been removed from opensocket
callback. opensocket just opens a new socket and gives it back to
libcurl and libcurl will take care of the connect. sockopt_callback has
also been removed, as it is no longer required.

Added an example for demonstrating the usage of curl multi interface
with boost::asio in c++

After a research team wrote a document[1] that found several live source
codes out there in the wild that misused the CURLOPT_SSL_VERIFYHOST
option thinking it was a boolean, this change now bans 1 as a value and
will make libcurl return error for it.

1 was never a sensible value to use in production but was introduced
back in the days to help debugging. It was always documented clearly
this way.

1 was never supported by all SSL backends in libcurl, so this cleanup
makes the treatment of it unified.

The report's list of mistakes for this option were all PHP code and
while there's a binding layer between libcurl and PHP, the PHP team has
decided that they have an as thin layer as possible on top of libcurl so
they will not alter or specifically filter a 'TRUE' value for this
particular option. I sympathize with that position.

[1] = http://daniel.haxx.se/blog/2012/10/25/libcurl-claimed-to-be-dangerous/

Since automake 1.12.4, the warnings are issued on running automake:

  warning: 'INCLUDES' is the old name for 'AM_CPPFLAGS' (or '*_CPPFLAGS')

Avoid INCLUDES and roll these flags into AM_CPPFLAGS.

Compile tested on:
  Ubuntu 10.04 (automake 1:1.11.1-1)
  Ubuntu 12.04 (automake 1:1.11.3-1ubuntu2)
  Arch Linux (automake 1.12.4)

The URL we used before is the one that goes directly to 'add' a bug
report, but since you can only do that after first having logged in to
sourceforge, the link often doesn't work for visitors.

Bug: http://curl.haxx.se/bug/view.cgi?id=3582408
Reported by: Oscar Norlander

Bug: http://curl.haxx.se/bug/view.cgi?id=3582407
Reported by: Oscar Norlander

It does so in a streaming manner using the "Streaming HTML parser".

This is a minor change in behavior after having been pointed out by Mark
Tully and discussed on the list. Initially this case would internally
call poll() with no sockets and a timeout which would equal a sleep for
that specified time.

Bug: http://curl.haxx.se/mail/lib-2012-10/0076.html
Reported by: Mark Tully

... in order not to leak memory on initializing an SSL library.

Reported by: Tomas Mlcoch

Minor change to recently introduced function.  BC breaking, but since
curl_multi_wait() doesn't exist in any releases that should be fine.