set names in dmvnorm

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mvtnorm@263 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
remove dim if necessary

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mvtnorm@264 edb9625f-4e0d-4859-8d74-9fd3b1da38cb