Import existing bus lines

A quick rough draft of the import GTFS feature, using the [AVAIL API](http://api.availabs.org/gtfs/). (This is not the intended final UI.)

Works well, but relies on exact city matches to find the corresponding bus lines. Most places have much fuzzier names. (E.g. try SF or Atlanta, but not New York). This (and performance) is going to be a big problem with relying on this API.

@invisiblefunnel, I'm wondering if a better approach is to use the new job queue you developed to bring in GTFS from [GTFS Data Exchange](http://www.gtfs-data-exchange.com/api) on a regular basis. Then, when someone creates a map we can do a spatial queries for agencies that have routes inside the area and offer those routes.

Thinking even bigger, would it make sense to change our underlying database structure to more closely match GTFS? It would make both import and export to GTFS easier, and let us more easily use existing analytics tools like OTP. We could act as a platform (both web services and nice UI) for GTFS.

![screen shot 2014-06-01 at 8 12 40 am](https://cloud.githubusercontent.com/assets/1435836/3141921/2031d21c-e9a0-11e3-8e94-0b53e10790f5.png)