rm-logfiles

major cleanup;
added eq_sig;
added print_sg (full contents), pprint_sg (stamps only);
added certify_typ, certify_term;
changed read_typ: result now certified;

#! /bin/sh
#rm-logfiles: remove useless files from subdirectories
rm log */make*.log */make*.log.gz */make*.log.z
rm */test
rm */.*.thy.ML
rm */ex/.*.thy.ML
rm HOL/Subst/.*.thy.ML