Add get_rattail_app() method for view supplements

tailbone/views/master.py

@@ -5585,6 +5585,9 @@ class ViewSupplement(object):
         self.rattail_config = master.rattail_config
         self.Session = master.Session
 
+    def get_rattail_app(self):
+        return self.master.get_rattail_app()
+
     def get_grid_query(self, query):
         """
         Return the "base" query for the grid.  This is invoked from