Item endpoint handler
POST/accounts/:_id
:param url: the url that led here :param lookup: sub resource query
.. versionchanged:: 0.2 Support for sub-resources. Relying on request.endpoint to retrieve the resource being consumed.
.. versionchanged:: 0.1.1 Relying on request.path for determining the current endpoint url.
.. versionchanged:: 0.1.0 Support for PUT method.
.. versionchanged:: 0.0.7 Using 'utils.request_method' helper function now.
.. versionchanged:: 0.0.6 Support for HEAD requests