Changes

Summary

1. merged
2. eliminated spurious Unicode, which is in conflict with Isabelle symbol interpretation;
3. pro-forma selection for improved error message;
4. eliminated without magic name;
5. NEWS;
6. always build with full results; always print unfinished sessions;
7. clarified name;
8. isabelle process -d; proper args;
9. tuned signature;
10. support for Poly/ML heap hierarchy, which saves a lot of disk space;
11. clarified signature;
12. tuned signature;
13. less physical "logic" argument, with option -l like "isabelle console" etc.;
14. find heaps uniformly via Sessions.Store; tuned;
15. clarified modules;
16. clarified modules;
17. ML save_state under control of Isabelle/Scala;
18. clarified prompt: "ML" usually means Isabelle/ML;
19. record stamps of cumulative input heaps; tuned;