Let settings determine which batch handler to use for vendor catalog views.

tailbone/views/batch.py

@@ -366,7 +366,15 @@ class BatchCrud(BaseCrud):
 
     def __init__(self, request):
         self.request = request
-        self.handler = self.batch_handler_class(config=self.request.rattail_config)
+        self.handler = self.get_handler()
+
+    def get_handler(self):
+        """
+        Returns a `BatchHandler` instance for the view.  Derived classes may
+        override this as needed.  The default is to create an instance of
+        :attr:`batch_handler_class`.
+        """
+        return self.batch_handler_class(self.request.rattail_config)
 
     def fieldset(self, model):
         """