----------------
- Python 3.7+ support.
[rnix, jensens]
- Try to translate plain error message in ``error_renderer`` in case of no
``message_tag`` defined.
[jensens]
- Add ``valid_class`` and ``valid_class_default`` as opposite of ``error_class``
and ``error_class_default`` to mark extracted values as valid.
[jensens]
- Add ``button`` blueprint.
[jensens]
**Internals:**
- Remove usage of ``Nodespaces`` behavior.
[rnix]
- Replace deprecated use of ``Nodify`` by ``MappingNode``.
[rnix]
- Replace deprecated use of ``NodeChildValidate`` by ``MappingConstraints``.
[rnix]
- Replace deprecated use of ``Adopt`` by ``MappingAdopt``.
[rnix]
- Remove ``NodeChildValidate`` and ``Adopt`` behaviors from ``WidgetAttributes``.
[rnix]
- Add ``push_state`` and ``pop_state`` to factory. Used in ``YafowilTestCase``
for saving and restoring factory state. This is needed when yafowil tests run
in compound with foreign tests to avoid breaking possible custom factory
configuration.
[rnix]
**Breaking changes:**
- Remove B/C behavior of ``callable_value`` function. No longer calls callable
without parameters as fallback. Always expect widget and data arguments in
signature.
[jensens]
- ``datatype`` converters now always gets passed the raw extracted value only.
Prior to removing B/C behavior from ``callable_value`` it was possible to use
callables taking widget and data as arguments returning the real converter
callable. This behavior was never intended to be supported for datatype
conversion.
[jensens]