Throw an error if IP lookup doesn't find anything

Improved other error messages and made test descriptions unique
Fill in traits->ip_address when creating a model from a database record
Throw a GeoIP2::Error::IPAddressNotFound exception if the IP address isn't in our database
Make sure we can safely call $model->X for each record a model contains

Make the queries_remaining attr for the MaxMind record class not required
since it won't be know when reading a local database.