moved from doc

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/desirability@7 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
moved to vignettes dir

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