allow to optionnaly define some columns title that should not be translated, this is very usefull when doing some dynamic listbox where columns title comes from properties of ERP5 documents and we do not want to translate them

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@23359 20353a03-c40f-0410-a6d1-a30d3c3de9de