CA-143826: When in Notifications view, the context should be empty
-I defined save and restore selection functionality in SelectionBroadcaster and implemented them in SelectionManager. The NavigationPanel now uses these to: 1) save the current Selection (context)  when the user switches to the Notification view, 2) to restore previous selection when switching away from the Notifications view.
Merge pull request #202 from GaborApatiNagy/CA-143826

CA-143826: When in Notifications view, the context should be empty