using audio context manager function (#243)

* using audio context manager function

* updated pxt reference

* trigger build

sim/state/sounds.ts

@@ -16,25 +16,8 @@ namespace pxsim.SoundMethods {
         return incr(buf)
     }
 
-    export function uint8ArrayToString(input: Uint8Array) {
-        let len = input.length;
-        let res = ""
-        for (let i = 0; i < len; ++i)
-            res += String.fromCharCode(input[i]);
-        return res;
-    }
-
-    export function play(buf: RefBuffer, volume: number) {
-        if (!buf) {
-            return Promise.resolve();
-        }
-        return new Promise<void>(resolve => {
-            let url = "data:audio/wav;base64," + btoa(uint8ArrayToString(buf.data))
-            audio = new Audio(url)
-            audio.onended = () => resolve();
-            audio.onpause = () => resolve();
-            audio.play();
-        })
+    export function play(buf: RefBuffer) {
+        return pxsim.AudioContextManager.playBufferAsync(buf);
     }
 
     export function stop() {