Changes

Summary

1. tuned;
2. discontinued somewhat pointless cronjob.options -- compile-time constants are sufficient;
3. timeout as in former isatest-makeall;
4. more robust quasi-unique name;
5. clarified signature: more static types;
6. clarified hg.id operation, with explicit tip as default;
7. added remote_build_history tasks: parallel on several remote hosts; isabelle_identify: use self repos for robustness; more logger context: options and ssh; setup repository clones on demand; clarified target repositories;
8. added setup_repository; clarified root: expanded in target environment;
9. more operations;
10. expand relatively to given environment, notably remote HOME;
11. tuned;
12. tuned signature;
13. tuned;
14. clarified treatment of non-text bytes;
15. remove invocation of build_history: results are reported via stdout;
16. clarified signature;
17. identify release;
18. prefer Isabelle standard Path;
19. clarified logs;
20. publish directly on webspace;
21. Jenkins: don't build in system mode