replaced obsolete FactIndex.T by Facts.T (cumulative version, assumes that facts are only added to unfinished theories); removed unused get_thm(s)_closure; removed obsolete fact_index_of, valid_thms, thms_containing(_consts);
replaced obsolete FactIndex.T by Facts.T (cumulative version, assumes that facts are only added to unfinished theories);
removed unused get_thm(s)_closure;
removed obsolete fact_index_of, valid_thms, thms_containing(_consts);

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