GladeApp GladePointerMode icons and devhelp icon are now registered as icon names

GladeWindow: replaced deprecated gtk_tool_button_new_from_stock() with
gtk_tool_button_new() + gtk_image_new_from_icon_name() to create actions tool items

GTK+ Catalog, glade.glade: replaced every stock icon with the corresponding icon name
TODO: the only stock icon that does not seem to have a replacement is gtk-edit