Summary
- more conservative update of Haskell stack (amending 04e54f57a869): 13.0 still lacks notable packages like "Agda" or "darcs";
- merged;
- clarified sessions_deps, according to Isabelle/MMT usage;
- tuned signature: for other dump-like tools;
- unused;
- tuned;
- clarified defaults via system options;
- added bib-file
- tuned headers etc, added bib-file
- tuned style and headers