* libnautilus-extensions/nautilus-global-preferences.c:
(nautilus_global_preferences_get_enabled_sidebar_panel_view_identifiers),
(nautilus_global_preferences_get_disabled_sidebar_panel_view_identifiers):
* libnautilus-extensions/nautilus-global-preferences.h:

Add a function that returns the disabled sidebar panels.  Needed
so that on-the-fly sidebar panel toggling can be smart about
adding and removing views.

Also rename some variabled to make it obvious which are the enabled
and disabled lists.