Slight refactoring of the treatment of quantifiers
Renamed form_ things to syntax_ things, and syntax_prs to syntax_io
Finished plumbing the new GUI.

Need to change the treatment of variable renaming
Lots of bugfixes to all aspects of the new gui
Minor update to the documentation
Add '+' and '-' to increase and decrease the number of history lines.

Also a new command line flag -hist-lines with clamping to (0..20)