Updated CW tutorial.
* Summarized the list of steps to create a new cube.
* Added a subsection on writing entities.
* Added a subsection on modifying the schema and updating the corresponding instance.
""" CW - nevow/twisted client
:organization: Logilab
:copyright: 2001-2010 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
"""