add example

git-svn-id: https://svn.r-project.org/R/trunk@65922 00db46b3-68df-0310-9c12-caf00c1e9a41
Correct error message from rgb().

git-svn-id: https://svn.r-project.org/R/trunk@65924 00db46b3-68df-0310-9c12-caf00c1e9a41
Commented out class(x) <- NULL in [.POSIXct and [[.POSICct.


git-svn-id: https://svn.r-project.org/R/trunk@65926 00db46b3-68df-0310-9c12-caf00c1e9a41