* demos/gtk-demo/toolpalette.c (load_special_items): Demonstrate
gtk_tool_item_group_set_label_widget().
* gtk/gtktoolitemgroup.[h|c]: Rename the "item-group-name" property to
"label" because that is what it is. Likewise rename the functions.
Add a "label-widget" propert and get/set_label_widget() functions,
based on the same code/API in GtkExpander.
* gtk/gtktoolitemgroup.[h|c]: Rename the name property to item-group-name
and rename get/set_name() to get/set_item_group_name(), to avoid a clash with
GtkWidget::name.
* gtk/gtktoolpalette.h: GtkToolPaletteClass: Add padding for future use.
* gtk/gtktoolpallete.[h|cc]:
* gtk/gtktoolitemgroup.[h|cc]: Added a tool pallete container widget,
with groups of toolbar items that can be shown as a grid of icons
or a list of names.
* gtk/Makefile.am:
* gtk/gtk.h:
* gtk/gtkmarshal.list: Mentioned the new files.
Bug #567729
