SEPTA: visual redesign

As promised, a visual redesign of the SEPTA IA to match the NJT one. Fixes #862 

Unfortunately, the API doesn't tell us if the train is boarding, nor does it give the track number.

![screenshot - 08192014 - 12 55 43 pm](https://cloud.githubusercontent.com/assets/4411471/3969600/457fdedc-27c2-11e4-8c41-3fa0477a3cf9.png)

In testing this, I noticed that you had to spell the station how they want it (e.g. You can't say "paoli to 30th street", but "paoli to 30th street station"). Assuming that they're getting the data from the GTFS feed, I can see if I can generate a stops.txt and guess an station from the user's input.

**Edit:** Implemented the above. `stops.txt` can be updated with `curl njt-api.appspot.com/septa/stops > stops.txt`.

![screenshot - 08192014 - 02 58 39 pm](https://cloud.githubusercontent.com/assets/4411471/3971366/f5ca2ce2-27d2-11e4-9cf7-fa5d69661da4.png)

Add comments to the functions to describe what they do.