add remove notification button + handle removed/added notifications

Quick Notifications now correctly refreshes when a new Notification arrives or an old is deleted, altough i couldn't get the indicator to recognize the change.
 
Also added a button the remove a notification: 
![device-2014-08-14-145546](https://cloud.githubusercontent.com/assets/1175520/3931671/c31d2732-245c-11e4-8149-4539231a8ae3.png)