added type cases/cases_tactic, and CASES, SUBGOAL_CASES; added consume rule; support named case conclusions; tuned interfaces;
added type cases/cases_tactic, and CASES, SUBGOAL_CASES;
added consume rule;
support named case conclusions;
tuned interfaces;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle