On trip, change inbound/outbound to 0/1
On trip, change inbound/outbound to 0/1

GTFS uses to distinguish trips that have the route ID, but go in
different directions.  Outbound/Inbound are suggested interpretations,
not part of the spec.

Fixes #32.

inmagik/django-multi-gtfs,inmagik/django-multi-gtfs,tulsawebdevs/django-multi-gtfs,tulsawebdevs/django-multi-gtfs,inmagik/django-multi-gtfs,inmagik/django-multi-gtfs