+ Added keydown() as a native function to RPGCode.

* Some more refactoring.

Signed-off-by: swordmaster2k <b00056835@student.itb.ie>
* Refactored render, plugins, and movement, source code. Updated licensing
  , removed inline ifs, whiles, etc. Removed unused code.

Signed-off-by: swordmaster2k <b00056835@student.itb.ie>
- Reverted registerFonts fix.

Signed-off-by: swordmaster2k <b00056835@student.itb.ie>