Add protection against XSS

In my app the following code opens a dialog box with "hi" :
`Notification.success("Some message alert('hi')")`

It shows that my app was vulnerable to XSS because Notification was used in that sort of way : `Notification.error("got an error : "+myError);`

And myError is a string that can come from anywhere, and is unsecure.

My fix was to decore Notification service and apply $sanitize on strings.