Summary
- clarified signature;
- clarified modules;
- clarified modules; clarified transactions;
- clarified modules: Build_Log.private_data provides raw data access without transaction_lock;
- more thorough transaction_lock;
- obsolete, see also a5896fe040dd;
- removed obsolete/broken isabelle_scala_script wrapper (see also abf9fcfa65cf);
- provide src/Tools/Demo as example for system component with Isabelle/Scala tool;