fix simulator support for music

sim/state/music.ts

@@ -0,0 +1,29 @@
+namespace pxsim {
+    export class SpeakerState {
+        frequency: number;
+        ms: number;
+    }
+    
+}
+namespace pxsim.music {
+
+    export function playTone(frequency: number, ms: number) {
+        const b = board();
+        b.speakerState.frequency = frequency;
+        b.speakerState.ms = ms;
+
+        runtime.queueDisplayUpdate();
+        let cb = getResume();
+        AudioContextManager.tone(frequency, 1);
+        if (ms <= 0) cb();
+        else {
+            setTimeout(() => {
+                AudioContextManager.stop();
+                b.speakerState.frequency = 0;
+                b.speakerState.ms = 0;
+                runtime.queueDisplayUpdate();
+                cb()
+            }, ms);
+        }
+    }
+}