Update zip db with data from public.opendatasoft

[Tecktron]

Just an idea but it would be nice to switch to a more continuously updated dataset for zip codes, such as: https://public.opendatasoft.com/explore/dataset/georef-united-states-of-america-zc-point/

Thanks!

[ChrisjanWust]

I've got a coverage of 93% on 10'000 records. Have double checked missing zip codes on USPS. Pretty disappointing.