Review class OwnIdentity getters/setters for non-cloned Date objects:
- Date is mutable so we should clone it in getters and setters
- Document why we clone it
- At places where it is already cloned, remove wrongly documented reason of "to prevent duplicate usage of db4o-stored objects" - Date is a db4o-primitive such as int, String, etc - so this does not apply.
- This is part of resolving https://bugs.freenetproject.org/view.php?id=6074