Build system rewritten from scratch for all platforms

We have rewritten our CMake based build definitions from scratch, and now all
platforms can use the system to build *mangos-zero*, including servers, tools
and API documentation.

A [CMake](http://www.cmake.org/) version 2.8.x or newer is required due to
several fixes for the Express editions of Visual Studio in this branch.

Changes in the build system
---------------------------
* Project files generated for Visual Studio and QtCreator will now include
  source and header grouping just as if the project files were created by
  these environments.

* Building *mangos-zero* using MinGW and experimental Clang compilers on
  Windows is now supported.

* The mpq library required to build the map tools builds on Windows, too.

* The recast navigtaion library has been upgraded from revision 252 to 256.

* _CRT_SECURE_NO_DEPRECATE and _CRT_SECURE_NO_WARNINGS defines previously
  added to source files to prevent Windows from complaining are now handled
  by CMake and added when generating Visual Studio project files.

* The map extractor, vmap extractor, vmap assembler and the movement map
  generator are now part of the build process and build properly on Windows.
  All map tools have moved from the `contrib` directory to `src/tools/`.

* Includes in several sources have been fixed.

* Generation of API docs with Doxygen is now handled by a CMake module,
  and will work instantly if you have Doxygen installed.

* Debug output now will be enabled for Debug builds (see CMAKE_BUILD_TYPE).
  You no longer have to pass a flag for this.

* Libraries by mangos-zero have now been prefixed with `mangos-`.

* The game library has now been split into multiple libraries, and the
  Auction House bot, battleground support and outdoor PvP are now their own
  modules.

* SOAP bindings can now be switched on/off using the WITH_MOD_SOAP CMake
  parameter.

* The included CMake Find_ modules have been rewritten to work with current
  versions of the dependencies.

* Git version and build information will now be extracted using only Git.
  A Git installation is now mandatory to build with version information.
  If Git is available, version information will include branch information.

Signed-off-by: Daniel S. Reichenbach <daniel@kogitoapp.com>