[project @ 1999-07-07 15:27:27 by simonmar]

- charge 1 for a case expression

- give a discount of opt_UF_ScrutConDiscount each time a constructor
  is scrutinised

(previously a case expression was not charged for at all, and the
discount for a scrutinised constructor was (opt_UF_ScrutConDiscount *
tyconFamilySize).  In 4.02, a case expression was also charged
tyconFamilySize to balance the discount, but this had the disadvantage
of charging for alternatives which may not be present in the actual
case expression).