tidying

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23520 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
polygamma working for all n

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@23521 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e