more private notifications

[goandgetoutta]

Since the display is always on and now big enough that people could glance on it, I think it would be nice to add an option to display the contents of a notification only if a button is pressed.

There should still be a notification, but only a vibration and the app icon should appear. An interaction with the screen or buttons then should toggle the notification to unroll and show the contents.

It would be awesome, if you could toggle this on on a per app basis.