run periodic tasks

def idle_task(self):
        '''run periodic tasks'''
        if self.starting_motor:
            if self.gasheli_settings.ignition_disable_time > 0:
                elapsed = time.time() - self.motor_t1
                if elapsed >= self.gasheli_settings.ignition_disable_time:
                    self.module('rc').set_override_chan(self.gasheli_settings.ignition_chan-1, self.old_override)
                    self.starting_motor = False
        if self.stopping_motor:
            elapsed = time.time() - self.motor_t1
            if elapsed >= self.gasheli_settings.ignition_stop_time:
                # hand back control to RC
                self.module('rc').set_override_chan(self.gasheli_settings.ignition_chan-1, self.old_override)
                self.stopping_motor = False