Test: check lat/lon against known defaults from IP address databases #123

If column headers are lat and lon or similar, flag any pairs that match the (unhelpful) default locations from certain IP address databases.

For example, according to this article, if you try to map an unknown IP addresses in the US, the lat/lon will default to the location (38.0000, -97.0000) in Kansas, near the center of the continental US.

Flag any lat/lon pairs that match these known locations. It is good to be aware if your data's lat/lons should be treated as "Don't know / NA."