The WeatherDatabase doesn't need the voronoi code anymore but uses

The WeatherDatabase doesn't need the voronoi code anymore but uses
Dave Eberly's spherical interpolation code (found in the Lib/Math
directory). So it would be great if you could give him also a place
in the thanks file.  Changing the WeatherDatabse made actually a heavy
internal redesign necessary but no code outside the database is
affected (isn't code hiding great?).