Remove service hardcoding

[tylerharter]

In busSim.py, there's this FIXME:

    def _is_service_valid(self, day, service_id):
        # FIXME: hardcode in the service to be 95, just pick the first service id                                                                                                                              
        return (day == 1) & (service_id.str.startswith("95"))

As a result, when self.day is "monday", no services are found running that day.