changed Markup print mode to YXML -- explicitly decode messages before being issued; changed Output print mode to plain default -- no escaping; simplified pgml_sym: produce Pgml.pgmlatom, no special treatment of Ctrl/Raw; removed unused issue_pgips; removed obsolete delay_msgs feature -- the script parser never fails, but produces inline error markup; removed obsolete wrap_pgml; explicit transformation of messages (pgml_terms and message_content); remove obsolete split_markup workaround; misc tuning;