* initial commit of the new build system that will replace the current premake/Makefile system (NOTE: this is still very much wip and preliminary)
   * the goal of this is to have a build system that works on every platform out-of-the-box, is highly configurable and relatively easy to write (Makefiles are very limited, premake doesn't have enough abilities and also uses Makefiles -> simple shell script ftw)
   * the target platforms are osx, ios, linux, freebsd, openbsd and mingw (only tested on osx right now, thus wip and preliminary)
   * source file dependencies are not checked yet (but get written out to .d files) -> all files are always rebuild right now
   * threaded/multi-job building is not implemented yet, but will be
   * pkg-config is not used yet to check if libraries actually exist (but will be; note however that not all libraries are supported by pkg-config)
   * actual floor configuration is not implemented yet (enable/disable opencl/cuda/openal)
   * currently supported build modes are release, debug and release_opt
   * for all options and usage of the build script type: ./build.sh --help
   * the xcode project will still be maintained (although the actual targets might get replaced by simply calling the build script in the future)
   * lots of misc TODOs left ...