Updated game engine core to use SDL2. Removed forced opengl.
Added a AddResource method to ContentManager. Separated Image
and Texture class. You can load an image from disk by directly accessing
Image::LoadImage(..) method as well as calling the ContentManager.
Fixed keys enum to be SDL2 compliant. Temporarily deactivated the
Sound Engine and SDL timer until further debugging is done.
Updated all makefiles and headers. Added a SetResource() method
to Resource class. Reworked how Texture and Image width/height
behaves. Updated most of the engine to use c++ strings instead
of C strings. Added an Initialize and Shutdown method to Graphics.
TextBuffer is currently broken. Need fixing. Input polling is
also broken.
Fixed TextBuffer
Fixed keys mapping. Changed methods that used C string in mouse/keyboard
classes to c++ strings.