Latest GTFS route configs are not in sync with historic data

[exxonvaldez]

As Jose mentioned in #89 , we need to archive GTFS data because it updates regularly.

For example, between May 24 and June 11, the F outbound direction id changed from F____O_E00 to F____O_F00, with a new terminal ("Castro" instead of "17th and Noe") and new last stop id (33311). So attempts to show anything about F outbound trips will not find any data . Even if we add logic to fall back on older direction ids, we still have the problem of the stop list being out of sync also.

[exxonvaldez]

There seems to be a GTFS archive here that has each new version: https://transitfeeds.com/p/sfmta/60

[exxonvaldez]

With #207 we can process shapes for older GTFS data just by pointing the script at the archive mentioned above. However, that leaves the question of whether we can get historic Nextbus route configs, or if we should derive the equivalent of them from GTFS data.