Add counties

[rkiddy]

I am not even going to apologize for not seeing the other "Add Counties" pull-request. I mean, really, 7 years? Wow.

Anyways. Also, I just added the data. No extra loader code to run. Just a class for County and a "counties" list on each state and that is all.

I got this from the tables at:

https://www.census.gov/library/reference/code-lists/ansi.html

Maybe if it just the data and absolutely nothing else, it can go in? Otherwise, at least I can pull from my fork.