Simplify basic config switching

[Andreas Schnellbacher]

All highly configurable editors have one problem: If one has changed a setting (by mistake or for testing) it's hard to remember where it can be changed back. Therefore there should be added an option to switch between some basic configurations via one click.

Following items make sense:

1. User, CUA

   -  Modes   -> [ ] Matchchars
   -  Modes   -> [ ] Balance
   -  Modes   -> [ ] Syntax expnasion
   -  Keys    -> [x] Stream mode
   -  Keys    -> [ ] Block ... (3 items)
   -  Keys    ->     Keyset additions: [cuakeys]
   -  Marking -> [ ] Advanced marking
   -  Marking ->     Default paste: [char]
   -  Marking -> [ ] Sh-mark always extends mark
   -  Marking ->     Default mouse mark: [char]
   -  Marking -> [x] Drag always marks
   -  Cursor  -> [ ] Allow cursor everywhere

2. Programmer, CUA (default)

   -  Modes   -> [x] Matchchars
   -  Modes   -> [x] Balance
   -  Modes   -> [x] Syntax expnasion
   -  Keys    -> [x] Stream mode
   -  Keys    -> [x] Block ... (3 items)
   -  Keys    ->     Keyset additions: [cuakeys]
   -  Marking -> [x] Advanced marking
   -  Marking ->     Default paste: [char]
   -  Marking -> [ ] Sh-mark always extends mark
   -  Marking ->     Default mouse mark: [char]
   -  Marking -> [x] Drag always marks
   -  Cursor  -> [x] Allow cursor everywhere

3. Programmer, Standard EPM

   -  Modes   -> [x] Matchchars
   -  Modes   -> [x] Balance
   -  Modes   -> [x] Syntax expnasion
   -  Keys    -> [ ] Stream mode
   -  Keys    -> [x] Block ... (3 items)
   -  Keys    ->     Keyset additions: [-none-]
   -  Marking -> [x] Advanced marking
   -  Marking ->     Default paste: [block]
   -  Marking -> [x] Sh-mark always extends mark
   -  Marking ->     Default mouse mark: [block]
   -  Marking -> [x] Drag always marks
   -  Cursor  -> [x] Allow cursor everywhere

[Andreas Schnellbacher]

Fixed by changeset r2668.