GeoCoordinates needs a few more things

[Dunbaratu]

After playing with rovers for a few days, I've come to the conclusion that GeoCoordinates are a bit lacking in the following ways that should be addressed:

1: They always assume you meant the current SOI body. There should also be a way to get the LATLNG position of a body your vessel is not currently orbiting (i.e. get a LATLNG for Duna while you're still on Kerbin, to help with planning things.)

2: A LATLNG is essentially a point in a 2D polar space representing the surface of the northern, or southern hemisphere. An ordinary position vector, on the other hand is a point in 3D Cartesian coordinates. There exist some methods in the KSP API to convert between these two, but we don't expose them to the script. We should. It would be handy to get the 3D universe coords that correspond to a LATLNG (and what the hey, we may as well include the altitude at the LATLNG to get things like "what are the 3D coords of a spot at 20km above sea level at 45 deg north, 20 deg east?". We can also go the other way around and get the (LAT,LNG,Altitude) of the surface directly under a 3D XYZ coordinate.