Added editor support for Icon View.
* plugins/gtk+/glade-gtk.c, plugins/gtk+/gtk+.xml.in: Added editor support for Icon View. * plugins/gtk+/glade-cell-renderer-editor.c: Export a new function to get the model from the renderer regardless of the layout type. * plugins/gtk+/glade-treeview-editor.c: Now supports editing any view that can have a model, and pops up the store editor automatically on the right of the normal widget editor. svn path=/trunk/; revision=2051