Initializing rate property to 1

Author: pavle-goloskokovic

src/sound/noaudio/NoAudioSoundManager.js

@@ -8,6 +8,7 @@ var NoAudioSoundManager = new Class({
         this.sounds = [];
         this.mute = false;
         this.volume = 1;
+        this.rate = 1;
     }
 });
 module.exports = NoAudioSoundManager;