when a view fails, instead of also executing during
	a normal quit. This is a starting point for putting
	some UI at the failure.

	* src/nautilus-window.c:
	(nautilus_window_disconnect_view): New function to disconnect
	the signal handlers on a view that were established in
	nautilus_window_connect_view.
	(view_disconnect): foreach-style wrapper for _disconnect_view.
	(nautilus_window_destroy): Call _disconnect_view on each
	sidebar panel, and on the content view.
	(nautilus_window_connect_view): Added comment and updated
	for a name change.
	* src/nautilus-window-manage-views.c:
	(nautilus_window_view_failed): Renamed from
	"nautilus_window_view_destroyed" since it's (now) only
	called in the case of a failure.
	(nautilus_window_has_really_changed): Call _disconnect_view.
	(nautilus_window_load_content_view): Replaced
	_connect_content_view with _connect_view.
	* src/nautilus-window-private.h: updated prototypes to match
	previously-mentioned changes.