IconInfo: Deprecate some methods.

* gtk/src/iconinfo.hg: Deprecate set_raw_coordinates(),
  get_embedded_rect(), get_attach_points() and
  get_display_name(), using the mostly useless deprecation comments
  from GTK+:
  https://git.gnome.org/browse/gtk+/commit/gtk/gtkicontheme.c?id=84bc9bba4214ac4dc05cb029b45bffbb84fa1393