Fixed repetitive freezing of IDE when connection drops.
when connection lost error was beeing displayed, the involved wxYield
was calling pending plc status periodic update, itself trying to use connector.
At that time connector is still not destroyed and connection
is attempted again when calling GetPLCStatus.
=> Hack : Ensure connector is destroyed before reporting error.

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