CHIP-8 virtual machine emulator - Load chip8 ROMs in the prime

[Mark Power]

I've fixed the display scaling problem so that the whole of the HP Prime screen is used and tidied up a few things. You now don't see the icon.png file in the list of ROMS to play.

I've included Breakout, Pong2, Space Invaders and Tetris in the zip file for you to play as samples.

Speed is the next thing to improve and then I'll add SChip functions so you can play the more advanced games.

Anyone feeling adventurous can press the D (Define) key during a game and drop into the Prime debugger.