wenzelm [Thu, 22 Dec 2005 00:28:51 +0100] rev 18465
simplified setup: removed dest_concls, local_impI, conjI;
improved handling of simultaneous goals: split cases;
simplified treatment of mutual rules, which are now specified as a list
instead of object-level conjunction (cf. set/type/rule);
moved join_rules to RuleCases.mutual_rule;