message: adding MetalSynth export
diff: @@ -2,3 +2,4 @@ export { Synth } from "./Synth";
  export { Sampler } from "./Sampler";
  export { PolySynth } from "./PolySynth";
  export { MembraneSynth } from "./MembraneSynth";
  +export { MetalSynth } from "./MetalSynth";
  