Bugfix: STARE::ValueFromLatLonDegrees returning level instead of index

Global SpatialVectors xhat, etc., initialized after STARE api, led to corrupt interface and bad values. Now declaring xhat, etc., locally and hoping programmer defines them correctly. TODO: figure out appropriate way to have a global xhat, etc.

See issue https://github.com/michaelleerilee/STARE/issues/22 .