2.4.7:

* TreeModelFitler:
  - Really fix the constructor.
  - Warn when calling set_value() on the filter mdoel instead
    of the child model.
  - set_modify_func(): Make this work - don't ignore the value.
* TreeView:
  add_column_editable() operates on the child model if the model 
  is a TreeModelFiler. 
* Documentation:
  - Updated popup menu section and example, to use UIManager.
  - Added 2 TreeModelFilter examples.
  (Murray Cumming)