[FIX] Write x2many values in tuple directives [(6, 0, ids)]
[FIX] x2many fields are uactually nsupported for various reasons
[FIX] Unserialize the field in the fields table
[FIX] Remove field from _columns and run model.__init__
to augment unserialized field object with magic attributes
[FIX] Disarm cr.commit() called in _auto_init before all values
have been migrated successfully
[FIX] Remove unserialized field from serializion field values
[ADD] Also show the unserialization button on the embedded field
form on the model form