The implication is that set<Reference>() in the object of the parent form will not be called (and thus not has to be implemented/public).
If you want to suppress this behaviour, manually set "by_reference" to false.
* Added empty_value option on CountryField, LanguageField, LocaleField, TimezoneField
* Added missing date_pattern to DateTimeField
* Made the currency option on MoneyField required.
Fields can now easier support different data types in their underlying object.
These datatypes can be normalized to a single datatype using a normalization
transformer. The normalized value can then be transformed to the user's
representation with the value transformer (better name required?).