Avoid re-rendering popups on page reload when signed-in.

+ Fix incorrect merge off a46f698a31c167974fd892f98f8a8f22d4c97beb and
  and 4ff5a5299e63cedcc4b575d3489e0bc4cb42b97b.
+ This ensures that the correct tab is selected.
Fix sign-in when login view has been closed before.

+ Prohibit that the login view can close itself. Instead the Marionette
  region has to be closed.
  See: https://github.com/marionettejs/backbone.marionette/blob/v1.0.4/docs/marionette.view.md#view-close
+ Refactor commit: 5bbb5ecb2b9c5e30f506de1ac755131d218ae25c.