add convenience `.disconnectAndClear` function for experimenting.

js/pixl/public/index.html

@@ -210,6 +210,12 @@
		};
		pixl.connect();
        pixl.disconnectAndClear = function() {
            pixl.disconnect();
            pixl.world = {};
            pixl.redraw();
        }
	</script>
</body>
</html>