fix redrawing relatively to pixl.pos.

js/pixl/public/index.html

			var h2 = Math.round(pixl.window.h / pixl.size / 2);
			pixl.ctx.fillStyle = "black";
			for (var x = -w2; x < w2; x++) {
				for (var y = -h2; y < h2; y++) {
			for (var x = pixl.pos.x - w2; x < pixl.pos.x + w2; x++) {
				for (var y = pixl.pos.y - h2; y < pixl.pos.y + h2; y++) {
					var pt = pixl.world[[x, y]];
					if (pt !== undefined) {
						pixl.draw_pixl({x: x, y: y}, pt.color, {send: false});