- Explicitly request wish8.5 (some things don't work in 8.4).  I'm sure there's a better way to do that (8.6 would probably be fine too).
Closing window now calls graceful quit routine.
 - More generous line spacing (for readability, aesthetics and to emphasise wrapped lines)
 - Added select_none command.
 - Added strip_blank_lines transformation.
 - Added collapse_whitespace transformation.