Add validation functionality

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/metamisc@239 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
simplify requirements calibration functions

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/metamisc@240 edb9625f-4e0d-4859-8d74-9fd3b1da38cb