message: exporting missing Signal classes
diff: @@ -4,7 +4,9 @@ export * from "./AudioToGain";
  export * from "./GainToAudio";
  export * from "./Multiply";
  export * from "./Negate";
  +export * from "./Pow";
  export * from "./Signal";
  +export * from "./Scale";
  export * from "./Subtract";
  export * from "./WaveShaper";
  export * from "./Zero";
  