for window height)

	* libnautilus-extensions/nautilus-keep-last-vertical-box.h,
	* libnautilus-extensions/nautilus-keep-last-vertical-box.c:
	New files, subclass of GtkVBox that truncates contents to
	fit, except last item which is always kept. (GtkVBox in the
	same situation just merrily places its child widgets outside
	of its allocation.)
	* libnautilus-extensions/Makefile.am: Build the new files.

	* src/ntl-index-panel.c:
	(make_button_box): Use NautilusKeepLastVerticalBox so only
	as many command buttons appear as fit, and the "Open with ..."
	button always appears; also embed this box in a GtkHBox to
	get horizontal sizing the way we want it.
	(add_command_buttons): Add (not yet active) "Open with ..."
	button.
	(nautilus_index_panel_update_buttons): Throw away the
	GtkHBox containing the button box instead of the button
	box itself.