Remove grid, ~20% speedup
Use imagedata and display (4x speedup, but blurry in Chrome)
Manually scale up; 2x slowdown, but works for Chrome
Merge branch 'imagedata'

Conflicts:
	public/js/main.js
Skip drawing offscreen pixels
Merge pull request #3 from smittal/master

Another 60% speedup; now runs smoothly on my Moto X.