Changed distance of one degree latitude/longitude from fixed value 110.9km to value calculated according to WGS84 ellipsoid model. A bug is also corrected in auyrelhy for the location of the central sector (thanks to Pierre Lassegues for both hints)!

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/aurelhy@21 edb9625f-4e0d-4859-8d74-9fd3b1da38cb