* libnautilus-extensions/nautilus-directory-async.c
	(ready_callback_call),
	(nautilus_directory_call_when_ready_internal),
	(call_ready_callbacks):
	Made the fix so that call_when_ready works properly when a NULL
	directory is passed in.

	* libnautilus-extensions/nautilus-file.h:
	* libnautilus-extensions/nautilus-file.c
	(nautilus_file_call_when_ready): Fix for call_when_ready with
	a NULL file.
	(nautilus_file_ref), (nautilus_file_list_ref),
	(nautilus_file_list_copy): Filled out the operations on lists.

	* libnautilus-extensions/nautilus-gtk-extensions.h:
	* libnautilus-extensions/nautilus-gtk-extensions.c
	(nautilus_gtk_object_list_ref), (nautilus_gtk_object_list_copy):
	Filled out the operations on lists.

	* src/ntl-uri-map.c (got_metadata_callback): Factored out the
	call to async get_file_info to simplify the logic.
	(nautilus_navigation_info_new): Took out the check for NULL that
	Maciej mentioned in his notes below now that call_when_ready can
	handle things.
	(nautilus_navigation_info_cancel),
	(nautilus_navigation_info_free): Took out some excessive NULL
	checks when calling routines that work with NULL.