Max´-controlled siphons for liveness of S3PGR2

Current deadlock control approaches for S³PGR² (systems of simple sequential processes with general resources requirement) suffer from incorrect or restricted liveness characterisation based on the concept of deadly marked siphons (DMSs) or max-controlled siphons have been demonstrated. Non-live transitions may exist when there are no DMSs. It is live when all siphons are max-controlled - restricted since it may be live when not max-controlled. We replace it with a new liveness condition called max´-controlled siphons.