Make layout configurable and "variable"

Make layout configurable and "variable", provide 2 layouts (US Qwerty and Canadian French) and two variants ("left-handed" and "right-handed").
Organize better
Experiment with mappings, fix documentation
Exchange keys for Command Mode and Undo
Replace "variant" with "permutation"
Add user commands to change left-/right-handed
Format comments
Simplify layout and permutation keeping
Plan to avoid double loading in the future
Format comments and documentation
Experiment with doc mark-up
Edit my ideas
Make to-end-of-line motion consistent with ...

to-start-of-line.
Update README
Experiment with mapping for changing case
Add a description comment
Format comment mark-up
Permute <z>, <x>, <c>, <v>
Experiment with inserting blanks
Declare more unused keys