close #472361: omit password and bytes attributes in allowed mass-mailing keys
by fixing default implementation for allowed_massmail_keys() in the
Emailable pluggable mixin (cw.common.mixins).
Added test (in entities.test though), also fix CWUserTC classes conflicts in the test module.
"""cube-specific forms/views/actions/components
:organization: Logilab
:copyright: 2001-2009 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""