cleaning up after brian ripley's comments

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/diseasemapping@827 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
git-svn-id: svn://svn.r-forge.r-project.org/svnroot/diseasemapping@828 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
git-svn-id: svn://svn.r-forge.r-project.org/svnroot/diseasemapping@829 edb9625f-4e0d-4859-8d74-9fd3b1da38cb