Renaming to location code to postal code

Discovered that user apis no longer even use zip code. That being the
case, it makes more sense to simply have a universal postal code field
updating tests
upping minor version
Bumping back version

Previous PR will be yanked so syncing version to what was present for
last PR
Merge pull request #157 from cbdr/rename-location-code-to-postal-code

Rename location code to postal code