Divorce answer formats from suggested answer formats

Caveat:
(1) Breaks backwards compatiblity (because I now have the intention to backfill soon)
(2) Depends on changes in ke (spcifically answerForms being taken as an array)

Also:
- adds mixins JsonifyProps and Changeable
- adds Justin's changes (currentValue)
- es6ify (=>) the formExamples

Auditors: eater