* Add SFML support besides SDL. Choose with global macro USE_SDL / USE_SFML.
+ Small fixes to make it compile on MinGW (with Glad instead of GLEW -> option NO_GLEW)
* Add SFML support besides SDL (Part 3). Cleaned up some macros.
* Add SFML support besides SDL (Part 4). Small SFML fixes. Changed Spaces->Tabs
* Add SFML support besides SDL (Part 5). Cleaning up more macros + small fixes.
* Port to SFML. Removed all SDL code.
* Small changes
* Conversion functions to/from SFML types for Vector2/3 and Color.
* Removed unused SDL files
* Changes for SFML port
* Changes for SFML port
* Fixed line endings (probably?)
