#15 Additional Altitude info

[Stanislav Sokolov]

The same issue applies to:

geCoordinates.cs line 88
geLocation.cs line 62
geLookAt.cs line 75 & 84
geRegion.cs line 87 & 89
geGroundOverlay.cs line 119

Altitude sometimes uses Single and sometimes uses double type - Ideally it should be a class of its own like Longitude and Latitude.