'add to basket' loading animation not showing when fancy notifications is not active.

In Theme Engine v1 `WPEC_Fancy_Notifications` JS component, this line is hiding the 'add to basket' loading animation even when fancy notifications is not active.

```
$( 'div.wpsc_loading_animation' ).css( 'visibility', 'hidden' );
```

https://github.com/wp-e-commerce/WP-e-Commerce/blame/branch-4.0.0/wpsc-components/fancy-notifications/js/fancy-notifications.js#L32