Changes

Summary

1. merged
2. merged
3. merged
4. merged
5. more proof simplificaition
6. merged
7. maintain loaded_files for each theory;
8. clarified: more uniform results;
9. slightly more parallelism;
10. prefer sequential file-system access, but parallel parse;
11. tuned;
12. clarified pure_files, based on uniform loaded_files;
13. tuned;
14. tuned signature -- more readable output as Scala value;
15. more operations;