UTM reprojection

Updates the Geotrellis GTFS parsing endpoint to detect the UTM zone for the incoming data and reproject that data to the correct UTM zone. Further details in the code comments.

I've manually verified Zhengzhou and Philly, and they both end up with the proper projection (for the curious, you can generate a UTM SRID via something like: `'32' + <'7' if southern hemisphere, '6' if northern> + zone_num`)
Good call; I originally had it that way but then split it because I was running into Scala issues. But now that Scala's working there's no reason it can't be one function; fixed.