* src/glade-widget.[ch]: Added glade_widget_remove_property ()

	* src/glade-editor-property.c: Hide widget when no property loaded

	* src/glade-editor.c: Fixed packing up so that invisible children
	  dont screw up the layout.

	* src/glade-gtk.c: Removed "border-width" on action area and vbox
	  in GtkDialogs that expose them, also removed "spacing" on the
	  action area - these props are controlled by "content-area-border",
	  "button-spacing" and "action-area-border" style props on the dialog.

	* src/glade-property.c: Added #if 0 debugging code.