Undo part of the last change so that CheckboxMultiChoice doesn't not subclass ChoiceBase. It doesn't make much sense. Also, remove the noneOption 'cos that makes no sense at all.
Undo part of the last change so that CheckboxMultiChoice doesn't not subclass
ChoiceBase. It doesn't make much sense.
Also, remove the noneOption 'cos that makes no sense at all.

emgee/formal,emgee/formal,emgee/formal