st: Remove StIconType

GTK+ works by explicitly specifying a -symbolic suffix for all icons.
Do the same here.

https://bugzilla.gnome.org/show_bug.cgi?id=682540

js/ui/lookingGlass.js

@@ -869,7 +869,6 @@ const LookingGlass = new Lang.Class({
         let toolbar = new St.BoxLayout({ name: 'Toolbar' });
         this.actor.add_actor(toolbar);
         let inspectIcon = new St.Icon({ icon_name: 'gtk-color-picker',
-                                        icon_type: St.IconType.FULLCOLOR,
                                         icon_size: 24 });
         toolbar.add_actor(inspectIcon);
         inspectIcon.reactive = true;