Fix compiler warnings and an error on some plugins in NetBSD

Fix Chipmunk library for NetBSD

sr.ht NetBSD test build: disable ssl verification in git globally

sr.ht NetBSD test build: try with ssl verification disabled

sr.ht NetBSD test build: try to install rootcerts as root

Try sr.ht NetBSD test build again without rootcerts

Do a small fix, add unit tests and documentation

Try to fix sr.ht NetBSD build by installing rootcerts

Add/modify functions to implement 'character', "apply", 'generate' and "map"

* "apply" of other Lisps can now be done using Dern's 'eval'.
  'eval' can now handle both use cases (regular evaluation
  and "apply").

* "map/mapcar" of other Lisps can now be done using Dern's 'generate'.
   It can also be used to generate a collection of values (somewhat like
   std::generate_n in C++).

* 'character' creates a character from a number of the codepoint
   (for example {D+97}), or from a string containing a unicode
   character name (for example [greek small letter lambda]).

Add initial macro and template implementation

* Add initial implementation for macros and
  templates into Dern.

* Fix few things.

Update README.md

Update documentation

* Update build instructions for Microsoft Windows
  using MSVC. The previous .bat file is replaced
  with a python script that will download, extract
  and set up all the headers and libraries needed for building
  Dern plugins in Windows (for example SDL2, SDL2_image,
  SDL2_ttf, SDL2_mixer, PDCurses).

  Sadly, this adds Python 2.7.x as a tool dependency for Windows,
  but it makes building Dern in Windows _much_ easier. In most
  other systems the required libraries can be installed
  simply and quickly by giving a short command, but in
  Windows the number of steps required is quite overwhelming.

  So instead of printing user lines and lines of instructions
  on how to download required headers and libraries, extract them,
  copy some files, generate .lib files, and so on, we just do it
  using python; the script does everything and the user doesn't
  have to do anything.

Lightcube: fix color picking on some cases

* Fix color picking in game Lightcube in cases
  where the RED, GREEN and BLUE sizes are not
  8 by default.

MSVC build script: fix and add summary

* Fix MSVC build script; .lib files were generated
  in wrong place and the script didn't work after
  being run only once. After being run the second
  time, it started to work.

* Add summary with games and ANSI colors.

* Fix MSVC compiler warnings from nuklear plugin, sdl2 plugin
  and chipmunk plugin.

* Fix some of the MSVC compiler warnings from the external
  Chipmunk library.

Add python script for MSVC build, update and fix some code

* Replace Microsoft Windows .bat file for doing
  Visual Studio 2017 build with a python script.

  This adds Python 2.7 as a tool dependency in Windows,
  but it has the benefit, that the user doesn't have to
  download, extract and set up all the dependencies.

  The script does everything required to compile Dern,
  all the plugins and examples using Visual Studio 2017; it
  downloads all the library headers and libraries,
  extracts them, copies files, generates few .lib files,
  and then builds Dern, plugins and examples.

* Make rest of the Dern plugins to compile with Visual Studio.

* Make some external code to compile with Visual Studio.

Fix and update couple of hints in Windows MSVC build script

Build embedding example, ncurses plugin and socket plugin with MSVC in Windows

Build binary library example in MSVC 'how-to-build'-script

* Build binary library example in Windows MSVC
  'how-to-build'-script.

* Enable binary plugins in the MSVC built Dern REPL.

Build Dern REPL in the MSVC 'how-to-build' script

* Build also the Dern REPL in the Microsoft Visual Studio C/C++
  'how-to-build' script. After this both the unit test runner and
  Dern REPL are built. Other programs/examples are still missing
  and have to be added.

* Fix crash of the REPL when built with MSVC; the third argument
  to main function must be named 'envp', or trying to access
  the environment variables will crash the application.

* Fix MSVC compiler warnings at level /W2 when building the REPL.

Fix (partially) Windows MinGW build