- introduce a new parameter "safe_substitute" to perform safe substitution, and enable it by default. This changes behaviour, but in previous case it was very hard for users to understand what's wrong in their notification message.
- add test for this new feature and for some substitution features that where not tested.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@33120 20353a03-c40f-0410-a6d1-a30d3c3de9de