Yafowil

------------------

- Ensure ``select`` tag not renders without closing tag if no options.
[rnix]

------------------

- Refactor yafowil plugin lookup. Improves performance.
[rnix, jensens]

- Use ``logger.warning`` instead of deprecated ``logger.warn``.
[rnix]

- Add ``yafowil.utils.callable_value``.
[rnix]

- Fix ``yafowil.utils.cssid`` to return unicode in order to prevent malformed
rendering in python 3.
[rnix]

------------------

- Do not dump string values as JSON data in ``yafowil.utils.as_data_attrs``.
[rnix]

- Rename ``yafowil.utils.generic_html5_attrs`` to
``yafowil.utils.as_data_attrs``.
[rnix]

----------------

- Python 3 Compatibility.
[rnix]

- Convert doctests to unittests.
[rnix]

- Cache results of ``yafowil.utils.get_plugin_names`` by namespace.
[rnix]

- Introduce ``yafowil.base.Factory.clear`` function. Used in tests to prepare
``yafowil.base.factory`` singleton as required.
[rnix]

- Create deepcopy of resources in ``YafowilResources.__init__`` to prevent
modification of the original resource definitions.
[rnix]

- Implement ``ExtractionError.__eq__`` to make them comparable.
[rnix]

- Do not access deprecated ``Exception.message`` any more in
``common.error_renderer``. Add ``msg`` attribute to ``ExtractionError``
directly and use this one to keep error translating sane.
[rnix]

- Add html5 data attribute support to ``form_edit_renderer``.
[rnix]

------------------

- Do not set ``persist`` property for ``proxy`` blueprint in factory defaults.
[rnix]

- Translate datatype label used to generate extraction error in
``generic_datatype_extractor`` if datatype conversion fails.
[rnix]

- Add ``generic_datatype_extractor`` to ``email`` blueprint. Allowed datatypes
are ``str`` and ``unicode``.
[rnix]

- Prevent ``KeyError`` in ``select_display_renderer`` if multivalued selection
and a value no longer available in vocab.
[rnix]

------------------

- Fix ``number_extractor``. Return ``UNSET`` if extracted value is ``UNSET``.
Check ``min`` and ``max`` for ``None`` explicitely to ensure ``0`` bounds
get considered.
[rnix]