don't resend world on redraw.

js/pixl/public/index.html

			return p !== undefined && p.color !== "white";
		}
		pixl.draw_pixl = function(pos, color) {
		pixl.draw_pixl = function(pos, color, options) {
			var color = color || "black";
			pixl.ctx.fillStyle = color;
			var screen_pos = pixl.to_screen(pos);
			pixl.ctx.fillRect(screen_pos.x, screen_pos.y, pixl.size, pixl.size);
			pixl.world[pos.x + "," + pos.y] = {color: color};
			if (pixl.online && !pos.remote) {
			var options = options || {send: true};
			if (pixl.online && options.send) {
				pixl.ws.send(JSON.stringify([{x: pos.x, y: pos.y, color: color}]));
			}
		}
				for (var y = -h2; y < h2; y++) {
					var pt = pixl.world[[x, y]];
					if (pt !== undefined) {
						pixl.draw_pixl({x: x, y: y}, pt.color);
						pixl.draw_pixl({x: x, y: y}, pt.color, {send: false});
					}
				}
			}
				var obj = JSON.parse(msg.data);
				if (obj.length !== undefined) {
					obj.forEach(function(p) {
						p.remote = true;
						pixl.world[p.x + "," + p.y] = {color: p.color};
						pixl.draw_pixl(p, p.color);
						pixl.draw_pixl(p, p.color, {send: false});
					});
				} else {
					pixl.world = obj;