MotC 1.0.1 (fullscreen mode)

Minor update to address full-screen mode issues.

• Now uses SDL2 "fake" full-screen (fits a borderless window to the screen, doesn't change the screen resolution), which works a lot better than the default SDL2 full-screen function.
• Added screenscale() function and SCALE_xxx constants to control how the output buffer is scaled to the available window/screen dimensions (see runtimelib.html for details).