Fixing dispose bug for VirtualJoysticksCamera

Babylon/Cameras/babylon.virtualJoysticksCamera.js

@@ -37,6 +37,7 @@ var BABYLON;
 
         VirtualJoysticksCamera.prototype.dispose = function () {
             this._leftjoystick.releaseCanvas();
+            _super.prototype.dispose.call(this);
         };
         return VirtualJoysticksCamera;
     })(BABYLON.FreeCamera);

Babylon/Cameras/babylon.virtualJoysticksCamera.ts

@@ -33,6 +33,7 @@
 
         public dispose(): void {
             this._leftjoystick.releaseCanvas();
+            super.dispose();
         }
     }
 }