Changes

Summary

1. merged
2. proper stack_limit;
3. clarified signature;
4. more accurate classpath for "isabelle scala";
5. proper check of registered Scala functions;
6. asynchronous build_session: notably for Scala.fulfill protocol commands during run;
7. clarified build_session protocol;
8. clarified signature;
9. clarified name;
10. more robust: explicit check for PIDE session;
11. tuned signature;
12. unused;
13. tuned signature;
14. check Scala source snippets from ML;
15. more robust isabelle.Functions --- avoid Java reflection with unclear class/object treatment;
16. init default context;
17. tuned message;
18. clarified signature;
19. tuned;
20. more brackets (see 2e8af171887f);
21. tuned message;
22. clarified signature; more operations;
23. unused;
24. more robust, notably for "isabelle scala";
25. clarified signature;
26. reorganised sorted_set_of_list
27. merged
28. simpler inductions