This bumps the minimal supported version of NSS to 3.12.x.

Configuration files such as curl_config.h and all config-*.h no longer exist
nor are generated/copied into 'src' directory, now these only exist in 'lib'
directory from where curl tool sources uses them.

Additionally old src/setup.h has been refactored into src/tool_setup.h which
now pulls lib/setup.h

The possibility of a makefile needing an include path adjustment exists.

Modify configure.ac to test for new CyaSSL Init function and remove
default install path to system.  Change to CyaSSL OpenSSL header and
proper Init in code as well.

Note that this no longer detects or works with CyaSSL before v2

The INTERNALS document suggested that compatibility should be
maintained with perl version 4, but this was untrue - scripts such as
chksource.pl and runtests.pl use perl5-isms.

Clarified the release procedure

curl_easy_duphandle() was not properly duping the ares channel. The
ares_dup() function was introduced in c-ares 1.6.0 so by starting to use
this function we also raise the bar and require c-ares >= 1.6.0
(released Dec 9, 2008) for such builds.

Reported by: Ning Dong
Bug: http://curl.haxx.se/mail/lib-2010-08/0318.html

It's not quite fair to list TFTP is a "crappy" member of the
libcurl family so I removed its mentioning.

removed trailing whitespace

renamed generated config.h to curl_config.h in order to avoid clashes when libcurl is used with other projects which also have a config.h.

in regard to C standard, third party libraries and operating systems etc.

internally