Calculate GTFS stop ID to Bustracker stop ID list when we get new GTFS data

[brendanbabb]

This is an enhancement. But we should be able to grab the lat longs for new GTFS stops.txt and do a search vs. the bustracker stops XML file (http://bustracker.muni.org/InfoPoint/XML/stops.xml) to find the stop with lat and long within x meters of the GTFS stop and determine that they are the same stop. Write the results out to the lib/stop_numbers_lookup.js file.

There are challenges still with old stops or duplicate stops or incorrect names, that we might need to hand correct, but this would get 90% of the stops and could check nightly (say 2am) after the GTFS load, which occurs at midnight, and only run if there is a new GTFS feed date.