simplify, test html5 data attrs
add recurrence field
- For the z3cform widget, remove widget adaptee registration from ZCML code and
  keep it in Python code. More appropriate z3c.form class hierarchy for the
  widget. Cleanup.
  [thet]

- Provide a RecurrenceField schema field which can be used instead of
  zope.schema.Text. This ensures that the recurrence widget is used even
  without form schema hints in bare z3c.form forms.
  [thet]
bugfix import
Remove the ParameterizedWidgetFactory in favor of form schema hints for
  widget parameters which is available since plone.autoform 1.4.
Merge branch 'new_field'