Fixed bug 1948 ("Open in New Window" menu item reuses existing
	window if it exists) by separating the explicit "open in new
	window" feature (always gives a new window) from the "open all
	items in new windows" preference (reuses window if one with the
	right location already exists).

	* libnautilus/nautilus-view-component.idl: Added new
	open_location_prefer_existing_window call. Renamed open_location
	to open_location_in_this_window and open_location_in_new_window to
	open_location_force_new_window for clarity.

	* libnautilus/nautilus-view.h:
	* libnautilus/nautilus-view.c:
	(nautilus_view_open_location_in_this_window),
	(nautilus_view_open_location_prefer_existing_window),
	(nautilus_view_open_location_force_new_window):
	* src/nautilus-view-frame-corba.c:
	(impl_Nautilus_ViewFrame_open_location_in_this_window),
	(impl_Nautilus_ViewFrame_open_location_prefer_existing_window),
	(impl_Nautilus_ViewFrame_open_location_force_new_window):
	* src/nautilus-...