threshold added to exports

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/lava@1019 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
merge

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/lava@1020 edb9625f-4e0d-4859-8d74-9fd3b1da38cb