GtkIconSource

[Havoc Pennington <hp redhat com>]

Hi,

See http://bugzilla.gnome.org/show_bug.cgi?id=51256

The problem is that GtkIconSource is not extensible.

Suggest we implement Alex's fix that we do it like GtkRcStyle, that
is, you can't allocate the icon source statically, you have to use
gtk_icon_source_new(). And have accessor functions.

People won't typically create icon sources anyway, probably they'll
use gtk_icon_set_new_from_pixbuf() or just an RC file. So we shouldn't
handicap our ability to add to GtkIconSource just to allow convenient
static initializers, since this is rarely-used functionality.

Havoc