History for UndoPolicies

??changed:
-
  The policy is currently that the user is allowed to undo
  transactions that were initiated by any member of
  the user folder where the user is defined.  Should this
  be changed?

  This policy has carried over to the updated undo mechansim which
  now makes use of getPhysicalPath() instead of AUTHENTICATION_PATH.
  The physical path of the user folder is now stored as a tuple in the
  transaction metadata.  However, the transaction filter can still
  recognize and use the former metadata format.

  With the new transaction metadata, it is *required* that all user
  management implementations wrap the user object before returning it
  from 'validate()'.  This can be done easily::

    return user.__of__(self)