Child improvements

- Make the tree view editable in child_translated_values_view.xml
- Make "get infos" button retreive basic info or if project doesn't exists, create it and retreive basic info 
- Add French, German and Italian descriptions in project_compassion_view.xml
- Add French, German and Italian country names in country_compassion.py
- Make project_compassion_view.xml (the view) as clear as possible
- Create English child description (child_description_en.py)
- Create Italian child description (child_description_it.py)
- Refactor child_descriptions_en|de|it.py 
Seems not very pythonesc... Please refer to child_description_fr._gen_list_string function for example.