add ConfigVariableFilename

direct/src/extensions/ConfigVariableFilename-extensions.py

@@ -0,0 +1,11 @@
+
+    def __len__(self):
+        return self.getValue().__len__()
+    
+    def __getitem__(self, n):
+        return self.getValue().__getitem__(n)
+    
+    def __setitem__(self, n):
+        value = self.getValue()
+        value.__setitem__(n)
+        self.assign(value)