add a fourth item to 'view box' defintion, dispctrl, so that
we can later globally sort all boxes instead of having view
boxes before component boxes.
'view' boxes order is configured through uicfg.primaryview_display_ctrl,
'component' boxes order through the cwproperty system.
"""this contains the cube-specific entities' classes
: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
"""