An important revision of the beautify commands that fixes (I think) all issues in git bug 68:  https://github.com/leo-editor/leo-editor/issues/68
- This attempts to take the lightest possible approach to beautification.  It is *not* a style enforcer!
- Wherever possible, either follows pep 8 recommendations or leaves whitespace alone.
- Eliminates most of the  the "pet peeves" disparaged by pep 8.
- Contains none of EKR's idiosyncratic preferences.
- Changed two unit tests in minor ways.

Leo build: 20141009092410