compare To
Compares this stop time to the other.
If tripId is not the same for both stop times, comparison is done by comparing tripId with String.compareTo. If the tripId is the same for both stop times, comparison is done by comparing stopSequence with Int.compareTo
Return
-1 if this stop time is before the other shape, 0 if both stop times are the same, 1 if this stop time is after the other