Initialize next step of simulation to be run.

def _init_step(self):
        """Initialize next step of simulation to be run.
        """
        self._age += 1
        self.env.age = self._age
        self._log(logging.INFO, "")
        self._log(logging.INFO, "\t***** Step {:0>4} *****". format(self.age))
        self._log(logging.INFO, "")
        self._agents_to_act = self._get_order_agents()
        self._step_processing_time = 0.0
        self._step_start_time = time.time()