growth curve vignette. leas TODOs


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/opm@528 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
add gridExtra to suggestions


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/opm@529 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
git-svn-id: svn://svn.r-forge.r-project.org/svnroot/opm@530 edb9625f-4e0d-4859-8d74-9fd3b1da38cb