add second VCO and more state

src/features/timbre/Timbre.js

@@ -2,5 +2,10 @@ import React from 'react';
 import VCO from './parameters/VCO';
 
 export function Timbre(props) {
-    return <VCO id="vco1" />;
+    return (
+        <div>
+            <VCO id="vco1" />
+            <VCO id="vco2" />
+        </div>
+    );
 }