Unity references for Lat/Lon should use consistent ordering

[david-rhodes]

For example, in a Vector2d, latitude is the x component and longitude is the y component.

Checking GeoToWorldPosition and MetersToLatLon, the components are being swapped at some point. This breaks the usage of Transform.GetGeoPosition(), for example.

[david-rhodes]

Turns out that ToString in Vector2d was reversing the order. This is because ToString is expected to return a very specific formatting to help compose URL strings for Mapbox API requests. Unsure if we will fix right now.