* Added "last_accessed" attribute to beaker.session.Session.
* Added "last_accessed" attribute to beaker.session.Session.

  This contains the _accessed_time value from when the session
  was *last* loaded, or None if the session was just created.
  It will be set correctly even if the session was invalidated due
  to a timeout, but not if the session was invalidated due to corruption.

--HG--
branch : trunk

enomado/beaker,masayuko/beaker,jvanasco/beaker