added fast_indexname_ord, fast_term_ord;
changed sort_ord, typ_ord, Vartab, Termtab: use fast orders;
added argument_type_of, dest_abs;
tuned;
* May 2005: Rafal Kolanski, NICTA
Substantially improved retrieval of facts from theory/proof context.
* May 2005: Florian Haftmann, TUM
Several new antiquotation.
* February 2005: Lucas Dixon, University of Edinburgh
Substantially improved subst method.
$Id$