Function pixelEqual

tests/tests.js:113–116

(left, right, idx)

	function pixelEqual(left, right, idx){
		var dt = 3;
		return	(Math.abs(left[idx] - right[idx]) < dt) && (Math.abs(left[idx+1] - right[idx+1]) < dt) && (Math.abs(left[idx+2] - right[idx+2]) < dt);
	}


	function _checkProgressEvent(evt){