* src/glade-catalog.[ch]:
  o manage all GModules with a hash table.
  o added glade_catalog_modules_close()

* src/glade-app.c:
  o call glade_catalog_modules_close() when the app finalize.
  o removed unnecesary headers.
* src/glade-gnome.c: fixed some warnings.

* src/glade-utils.c: slight optimization in function
  glade_util_get_type_from_name (), check if type is already registered.

* src/glade.h: removed unneeded #ifdef GLADE_H check.

* src/glade-widget-adaptor.[ch]:
  o removed module member from GladeWidgetAdaptorPriv since now we keep
    all the openned modules inside glade-catalog.c
  o added glade_abort_if_derived_adaptors_exist().