Summary
- A bunch of suggestions from Pedro Sánchez Terraf
- merged
- merged
- tweaked
- obsolete -- done by Isabelle/PIDE/ML;
- tuned whitespace --- avoid TABs;
- updated to Haskell stack-2.5.1, stackage lts-16.12, ghc-8.8.4;
- updated to postgresql-42.2.18;
- updated to jfreechart-1.5.1;
- updated to current cygwin-20201130, after 3.1.7-1 from 24-Aug-2020;
- Added tag Isabelle2021-RC0 for changeset 21ff9c1a4644