Update latlong2uscensus.py

Ryan ACTON (not ACTION)
Merge pull request #2 from michaelaoash/patch-2

Update latlong2uscensus.py
Update README.md

Added thanks to National Broadband Map which provides the API
Merge pull request #3 from michaelaoash/patch-3

Update README.md
added support for multiple returns
added example input file
Changed comma to tab in output file
FIPS substrings (state, county, tract, etc.) are now cumulative which facilitates matching to other data
Various minor changes including output format
Changed name of input file in examples