- adds a `#:timeout-lock-there' argument to `get-preference'
- fixes preference looup in `racket/gui'
- make preference names consistently use `GRacket' and consistently
fall back on `MrEd' names
- fix Emacs-style undo mode while we're at it
original commit: 98822cf1f989efd7c22f5d9587a65aeee29f26c0