add validation plot

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/metamisc@247 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
fix bracket issue

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/metamisc@248 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
improve frequency bars of validation plot

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/metamisc@249 edb9625f-4e0d-4859-8d74-9fd3b1da38cb