Move configuration and key bindings to separate file

config.js must be executed before game.js
Move Matrix class into separate file

matrix.js does not have any dependencies
Move Sprite class into separate file

sprite.js depends on config.js and matrix.js
Move Ship class into separate file

Ship inherits from Sprite, so ship.js depends on sprite.js
Move BigAlien class into separate file

BigAlien inherits from Sprite, so bigalien.js depends on sprite.js
Move Bullet class into separate file

Bullet inherits from Sprite, so bullet.js depends on sprite.js
Move AlienBullet class into separate file

AlienBullet inherits from Sprite, so alienbullet.js depends on sprite.js
Move Asteroid class into separate file

Asteroid inherits from Sprite, so asteroid.js depends on sprite.js
Move Explosion class into separate file

Explosion inherits from Sprite, so explosion.js depends on sprite.js
Move GridNode class into separate file

gridnode.js does not have any dependencies
Move Text class into separate file

text.js does not have any dependencies
Move initialization logic out of game.js into main.js

game.js now depends on text.js, config.js, explosion.js and asteroid.js (and Date and window).
main.js depends on jQuery, gridnode.js, sprite.js, ship.js, bullet.js, bigalien.js, config.js,
game.js, matrix.js, text.js and vector_battle_regular.typeface.js;
i.e. everything except alienbullet.js, asteroid.js and explosion.js.
Move jQuery and text utilities into lib directory
Move entities/objects into sprites directory

Load matrix.js after sprites in index.html
Move main files into core directory
Add readme and jstd+jasmine test framework