Added *city_region* functionality to obtain region codes from free geoip...

The basic GeoIP.dat database only includes country codes.
There is a free version of the GeoIPCity.dat database called GeoCityLite.dat that contains city and region codes for ip addresses. There is also a subscription only GeoIPRegion.dat database.

In order to obtain region codes from IP address, I added some functionality to open the appropriate database depending on what you are trying to accomplish. I also added and exposed a couple of functions that will allow you to pull the region codes from the city database.