refacotring various simulator features into pxt

sim/state/misc.ts

@@ -22,58 +22,6 @@ namespace pxsim {
         throw new Error("PANIC " + code)
     }
 
-    export namespace AudioContextManager {
-        let _context: any; // AudioContext
-        let _vco: any; // OscillatorNode;
-        let _vca: any; // GainNode;
-
-        function context(): any {
-            if (!_context) _context = freshContext();
-            return _context;
-        }
-
-        function freshContext(): any {
-            (<any>window).AudioContext = (<any>window).AudioContext || (<any>window).webkitAudioContext;
-            if ((<any>window).AudioContext) {
-                try {
-                    // this call my crash.
-                    // SyntaxError: audio resources unavailable for AudioContext construction
-                    return new (<any>window).AudioContext();
-                } catch (e) { }
-            }
-            return undefined;
-        }
-
-        export function stop() {
-            if (_vca) _vca.gain.value = 0;
-        }
-
-        export function tone(frequency: number, gain: number) {
-            if (frequency <= 0) return;
-            let ctx = context();
-            if (!ctx) return;
-
-            gain = Math.max(0, Math.min(1, gain));
-            if (!_vco) {
-                try {
-                    _vco = ctx.createOscillator();
-                    _vca = ctx.createGain();
-                    _vco.connect(_vca);
-                    _vca.connect(ctx.destination);
-                    _vca.gain.value = gain;
-                    _vco.start(0);
-                } catch (e) {
-                    _vco = undefined;
-                    _vca = undefined;
-                    return;
-                }
-            }
-
-            _vco.frequency.value = frequency;
-            _vca.gain.value = gain;
-        }
-    }
-
     export interface RuntimeOptions {
         theme: string;
     }