Added multi item action subform for generic list subtemplate and related code

apps/common/api.py

@@ -4,9 +4,15 @@ from django.db.utils import DatabaseError
 
 
 object_navigation = {}
+multi_object_navigation = {}
 menu_links = []
 model_list_columns = {}
 
+
+
+def register_multi_item_links(src, links, menu_name=None):
+    pass
+
 def register_links(src, links, menu_name=None):
     if menu_name in object_navigation:
         if hasattr(src, '__iter__'):