schedule-for-stop API call has incorrect headsigns

[devinbraun]

The API call schedule-for-stop doesn't provide correct trip headsign values for short lines.

Take, for example, the following call (any date will work):
http://realtime.sdmts.com/api/api/where/schedule-for-stop/MTS_75042.xml?key=org.onebusaway.iphone&date=2016-09-18

There is only one entry for the tripHeadsign element, "Santee", but in reality, there are shortlines to Qualcomm Stadium and SDSU, whose values are specified in the trips.txt file.

Other API calls do show the correct headsign for these individual shortlined trips.

[devinbraun]

google_transit.zip

Here are the GTFS files for the current build.