added WebAudioSound class

Author: pavle-goloskokovic

v3/src/sound/WebAudioSound.js

@@ -0,0 +1,11 @@
+var Class = require('../utils/Class');
+var BaseSound = require('./BaseSound');
+//  Phaser.Sound.WebAudioSound
+var WebAudioSound = new Class({
+    Extends: BaseSound,
+    initialize: function WebAudioSound(manager, key, config) {
+        // TODO update config duration
+        BaseSound.call(this, manager, key, config);
+    }
+});
+module.exports = WebAudioSound;