[UPDATE] implmentation of SDL1.2 -> SDL2.0 graphics migration. Create a temporary texture (for screen surface) which is no longer the screen. Use SDL_Window and SDL_Renderer to render to the screen, a texture generated at the end of the frame (in lieu of SDL_Flip()), from screen_surface. The game now shows in a window. Sound. check. Graphics. check. Still lots to do. Next up input/keyboard entry, which doesn't seem to be responsive