python3 support: pylint, W1633 # (round-builtin) round built-in referenced

because round behavior is changed to default behavior in Python3
(Banker round). It can cause slight differences in some cases.
Mostly graphical editors are affected, there could be single pixel differences.
Now I couldn't locate any visual differences in test programs.

These classes are intended for use server-side.

e.g. in a django view.py :

    from pyjs.jsonrpc.django import JSONService, jsonremote

    jsonservice = JSONRPCService()

    @jsonremote(jsonservice)
    def test(request, echo_param):
         return "echoing the param back: %s" % echo_param