- Setting 'id' (which changes the Global Storage key that
gets used) is a kludge when the existing module-instance
name can be used instead -- and **was** already used, as
a fallback when 'id' is not set. There's no point in having
two places to set a particular name.
- Rip out the docs for 'id' as well.
- Add documentation on the difference between single-selection
(the QML implementation) and model-selection (what the Widgets
version does).
- use updateGlobalStorage() for both single-selection and
model-based approaches, although the model-based one
needs extra parameters.
- complain about inconsistent settings and API calls (e.g.
setting a model and single-selection at the same time)
