better checking for making model sets

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/phrapl@153 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
got rid of unneeded print statements

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/phrapl@154 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
took care of corner case where maxval<minval

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/phrapl@155 edb9625f-4e0d-4859-8d74-9fd3b1da38cb