Thumbslider div is never destroyed on notification dismiss

[saurabhiam]

The thumbslider notification div is created on notification init, when close is called the notification closes but its div is never destroyed. The below code stays in the wrapper in which it was created:
<div class="ns-box ns-other ns-effect-thumbslider ns-type-warning ns-show"><div class="ns-box-inner"><span class="ns-close"></span></div>

Also, when notification.show(); is called multiple times, multiple divs are created and none of them are destroyed on close.

Tested rest of the notifications, div is destroyed in that case.