Longitude range in LatitudeLongitude's IsValid().

[kihyung-lee]

In struct LatitudeLongitude, the latitude and longitude ranges are set as follows:
Latitude: -90 to 90 degrees
Longitude: -90 to 90 degrees

This way, the latitude is correct, but the longitude doesn't cover half the Earth.
Typically, the longitude range is -180 to 180 degrees.
This range is also used when retrieving coordinates in a map app.
For example, Korea is between 124 and 132 degrees east longitude.
So, I don't think the IsValid() function can return an accurate boolean value.

[brnkhy]

@kihyung-lee that's a strange bug, looks like we weren't using that validation function (except a few tests) so we never noticed this, I'll fix this as soon as possible, thanks a lot!