Chip8 emulator written in javascript, seems to work reasonably correctly.

Based on this documentation:  http://devernay.free.fr/hacks/chip8/C8TECH10.HTM

Try the demo like so:

    ruby -run -e httpd . -p 9090

Then visit http://localhost:9090/index.html

TODO:

  * Complete the assembler
  * Finish writing an actual game
  * Add meta info to program json
    * Author, Description, etc
    * Key map (map actual keys to emulated keys on a per program basis)
    * Specify frames per second and instructions per second
    * Optionally, sync update screen to increase in dt