Changes

Summary

1. tuned -- prefer Config.T over Data;
2. proper "editor_tracing_messages=0" as in "isabelle dump";
3. tuned;
4. clarified build_options vs. job options;
5. more official handling of protocol messages, including export;
6. less redundant markup reports;
7. more accurate context position reports;
8. clarified signature;
9. clarified signature;
10. tuned;
11. clarified signature;
12. tuned signature;