remove some Big references from places that don't need them any more

https://bugzilla.gnome.org/show_bug.cgi?id=614516

js/ui/runDialog.js

@@ -1,6 +1,5 @@
 /* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
 
-const Big = imports.gi.Big;
 const Clutter = imports.gi.Clutter;
 const Gio = imports.gi.Gio;
 const GLib = imports.gi.GLib;