CONTRIBUTORS

removed not_const -- use Not instead;
add mk_not;

* 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.

$Id$