Bump minimum required CMake version

Bump minimum required CMake version to 2.8.12 now that it's released.

That will also avoid the following deprecation warning:

CMake Deprecation Warning at .../civetweb/CMakeLists.txt:2 (cmake_minimum_required):
  Compatibility with CMake < 2.8.12 will be removed from a future version of
  CMake.

V1.14 is completed and in a final test state.

Apparently such a statement is required (since there are unreproducible
issues without any description like #978), and projects containing "only"
templates and instructions for creating issues like
https://github.com/necolas/issue-guidelines/blob/master/CONTRIBUTING.md#bug-reports

This issue has been fixed a long time ago.
Closes #189

Fully automate (Linux) shell script for generating a certificate for HTTPS.
Passwords, country, company name, ... does no longer need to be entered in this version of the script.
All information is hard coded in the script and can be modified according to your needs.
The new script also shows how to use a root certificate - when adding this to the trusted root certification
authorities (in Windows), browsers will accept a https connection to localhost without any warning.

Note: These are all just DEMO certificates for localhost. Do not use them in production.

TODO: external interface

git log --format=oneline 3462be24..HEAD

git log --format=oneline 3462be24..HEAD

quick OpenSSL-3.0 API support

Extended support for WinCE ends in April 2021. CivetWeb has not been tested on
WinCE for the some releases. Remove dead code.

git log --format=oneline 8e243456..HEAD

git log --format="%aN" a9fb075f..HEAD | sort

docs/api/ fix link to mg_printf md page

The lua background state can export a log() function. This function can filter
the log by returning true (log) or false (do not log), or it can format a
log message before it is written to the log file by returning it as string.

Signed-off-by: Lorenzo Canepa <paperino1983@gmail.com>