[python2.6] careful: json-py provides a json package. We don't want that.
To simplify usage, import json via cubicweb.web
# pylint: disable-msg=W0614,W0401fromwarningsimportwarnwarn('moved to cubicweb.dataimport',DeprecationWarning,stacklevel=2)fromcubicweb.dataimportimport*