- simplify initialization of form._values (don't fill in with False)
- use UpdateDict for form._values (more consistent with x2many values)
- better/simpler API for getting save/onchange/all values
- don't reparse subview in O2MForm (already done by toplevel Form)
- guarantee that one2many fields always have an edition view
- add assignment on many2many fields
- add __getitem__/__setitem__ to access/assign fields with dynamic name
Part-of: odoo/odoo#127400