Cosmetics.

git-svn-id: https://svn.r-project.org/R/trunk@66593 00db46b3-68df-0310-9c12-caf00c1e9a41
Add some examples inside \dontrun.

git-svn-id: https://svn.r-project.org/R/trunk@66594 00db46b3-68df-0310-9c12-caf00c1e9a41
Avoid keeping outputs twice.

git-svn-id: https://svn.r-project.org/R/trunk@66595 00db46b3-68df-0310-9c12-caf00c1e9a41