from all volumes). Some loose ends are already reported in bugs
	2146, 2243, and 2244.

	* libnautilus-extensions/Makefile.am:
	* libnautilus-extensions/nautilus-merged-directory.h:
	* libnautilus-extensions/nautilus-merged-directory.c:
	Moved all the guts of NautilusTrashDirectory that are solely
	about having a single directory that's a union of a bunch of
	real directories into a separate base class. Also finished the
	implementation, leaving only unimportant loose ends.

	* libnautilus-extensions/nautilus-trash-directory.h:
	* libnautilus-extensions/nautilus-trash-directory.c:
	(get_volume_vfs_uri_if_writable), (find_directory_callback),
	(add_volume), (remove_trash_volume), (remove_volume),
	(add_one_volume), (volume_mounted_callback),
	(volume_unmounted_callback), (nautilus_trash_directory_initialize),
	(remove_trash_volume_cover), (trash_destroy),
	(nautilus_trash_directory_initialize_class):
	Added the code to find the trash on all vo...