systest: Use blitter for draw_hollow_rect(). Clearer API for set/clear_filled_rect(). Simplify virtual keyboard key-fill logic.
systest: Use blitter for draw_hollow_rect().
Clearer API for set/clear_filled_rect().
Simplify virtual keyboard key-fill logic.

keirf/Amiga-Stuff,keirf/Amiga-Stuff