Add support for batch execution options in Buefy themes

i.e. from "view batch" page

tailbone/views/batch/core.py

@@ -49,6 +49,7 @@ from rattail.progress import SocketProgress
 
 import colander
 import deform
+from deform import widget as dfwidget
 from pyramid.renderers import render_to_response
 from pyramid.response import FileResponse
 from webhelpers2.html import HTML, tags
@@ -800,6 +801,7 @@ class BatchMasterView(MasterView):
         """
         defaults = {}
         route_prefix = self.get_route_prefix()
+        use_buefy = self.get_use_buefy()
 
         if self.has_execution_options(batch):
             if batch is None:
@@ -818,10 +820,14 @@ class BatchMasterView(MasterView):
                     labels = kwargs.setdefault('labels', {})
                     labels[field.name] = field.title
 
+                # auto-convert select widgets for buefy theme
+                if use_buefy and isinstance(field.widget, forms.widgets.PlainSelectWidget):
+                    field.widget = dfwidget.SelectWidget(values=field.widget.values)
+
         else:
             schema = colander.Schema()
 
-        kwargs['use_buefy'] = self.get_use_buefy()
+        kwargs['use_buefy'] = use_buefy
         kwargs['component'] = 'execute-form'
         return forms.Form(schema=schema, request=self.request, defaults=defaults, **kwargs)