* Remove the logic from app-controller.coffee to focus the Public group
   on logout. This is no longer needed as the 'groups' service automatically
   updates the focused group if the previously focused group is removed.

 * Only emit the SESSION_CHANGED event on updates to the session state,
   not the initial app load, since initialization of the view is deferred
   until the session has already been loaded.

   Since the SESSION_CHANGED handler currently reloads the whole view,
   this avoids reloading the view twice on startup.

   Refactoring handling of SESSION_CHANGED to only update the relevant
   app state is left for a future refactoring.

T-105