Factor out raycasting routines, improve explosions, fix fullscreen button, optimise
Factor out raycasting routines, improve explosions, fix fullscreen button, optimise

fabiosantoscode/canvas-raycasting,fabiosantoscode/canvas-raycasting,fabiosantoscode/canvas-raycasting,fabiosantoscode/canvas-raycasting,fabiosantoscode/canvas-raycasting