Python runtime: call "OnIdle" tasks when py_eval FBs execution queue is empty.

This is usefull to execute slow operations that can be deffered from functions called by py_eval FBs.
User python code add a callable to "OnIdle" list made available in global scope.

# -*- coding: utf-8 -*-

# See COPYING.Runtime file for copyrights details.


def _(x):
    """No translation"""
    return x


Broken = _("Broken")
Started = _("Started")
Stopped = _("Stopped")
Disconnected = _("Disconnected")
Empty = _("Empty")