Provides essential methods related to Window Store application.
| advertisingIdentifier | Advertising ID. |
| arguments | Arguments passed to application. |
| InvokeOnAppThread | Executes callback item on application thread. |
| InvokeOnUIThread | Executes callback item on UI thread. |
| RunningOnAppThread | Returns true if you're running on application thread. |
| RunningOnUIThread | Returns true if you're running on UI thread. |
| windowActivated | Fired when application window is activated. |
| windowSizeChanged | Fired when window size changes. |