renamed kill_all to kill, in conformance with atp_kill command;
simplified/unified treatment of preferences;
check_thread_manager: CRITICAL due to global ref;
goal addressing via Thm.cprem_of;
reduced NJ basis library stuff to bare minimum;
List = FOL +
types list 1
arities list :: (term)term
consts Nil :: "'a list"
Cons :: "['a, 'a list] => 'a list"
end