ROOM_S_DARK_LONG	This property now replaces the old long desc
			reported when the player could not see in
			the room. ('A dark room.'). If this property
			is not defined, the old default will be used.
			Example:
			add_prop(ROOM_S_DARK_LONG,
				"A dark, misty forest. It is impossible "+
				"to see anything in the darkness.\n");

