added ProofContext.tsig_of -- proforma version for local name space only, not logical content;
added ProofContext.read_type_name_proper;
localized ProofContext.read_class/read_arity/cert_arity;
localized ProofContext.class_space/type_space etc.;
Identifiers of some old CVS file versions
=========================================
src/Pure/General/file.ML 1.18 6cdd6a8da9b9
src/Pure/thm.ML 1.189 4b339d3907a0 (referenced in 25f28f9c28a3 as "2005-01-24 (revision 1.44)")
src/Pure/type.ML 1.65 0d984ee030a1