Improve delaboration and pretty-printing for case

Now, the delaborator finds case expressions and converts them back to
the original. This makes :printdef work with these.
Follow instructions in comment and remove unused code
Fix Curses whitespace issue with test delab001
Merge pull request #1758 from david-christiansen/feature/case-delab

Improve delaboration and pretty-printing for "case"
Merge branch 'master' into keep-FFunction-and-FAny-types