Add self.cloning convenience indicator for master view

tailbone/views/master.py

@@ -123,6 +123,7 @@ class MasterView(View):
     editing = False
     deleting = False
     executing = False
+    cloning = False
     has_pk_fields = False
     has_image = False
     has_thumbnail = False
@@ -1129,6 +1130,7 @@ class MasterView(View):
         View for cloning an object's data into a new object.
         """
         self.viewing = True
+        self.cloning = True
         instance = self.get_instance()
         form = self.make_form(instance)
         self.configure_clone_form(form)