Fix subject encoding pb. when notifying bookmarked event by mail.
[r0.0.72] i18n + user's homepage refactoring

* orm.relation.Relation class has a new method _ (alias for gettext.tanslation).
* actions labels are now translated in access.view.access*.w3in_nav_link method.
* French translation for "My desk".
* Bookmarked posts are now integrated in "My desk".