updated index.php file



git-svn-id: svn://svn.r-forge.r-project.org/svnroot/sombrero@20 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
improved www page



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