update to Roxygen 4.0

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/openair@857 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
more documentation updates

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/openair@858 edb9625f-4e0d-4859-8d74-9fd3b1da38cb