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.

# pylint: disable=undefined-variable

from __future__ import absolute_import
from svgui.pyjs.jsonrpc.jsonrpc import JSONRPCServiceBase


class JSONRPCService(JSONRPCServiceBase):

    def serve(self):
        return self.process(request.body.read())

    def __call__(self, func):
        self.methods[func.__name__] = func
        return func