gtfs realtime? python 3.x support?

[fpurcell]

dbswarco asked (in issues #68):

I'm not clear on whether or not this repo supports realtime GTFS feeds. I did find this https://github.com/OpenTransitTools/gtfsdb_realtime but it hasn't been updated in a while and relies on Python 2.7 which is all but dead.

[fpurcell]

gtfsdb loads the static data, and gtfsdb_realtime loads realtime feeds, adding that information alongside the static data.
https://github.com/OpenTransitTools/gtfsdb_realtime/tree/rtp is the branch where I've been adding support for py 3.x (alongside https://github.com/OpenTransitTools/gtfsdb/tree/rtp).