r62950 was not applied to 3.0.1, which was already released

git-svn-id: https://svn.r-project.org/R/trunk@62993 00db46b3-68df-0310-9c12-caf00c1e9a41
unlist(x) now typically returns all non-list xs unchanged;
fixes format(<list>) when <list> has non-vector content

git-svn-id: https://svn.r-project.org/R/trunk@62995 00db46b3-68df-0310-9c12-caf00c1e9a41
Add getVignetteInfo function to be used for consistent listing of vignettes.

git-svn-id: https://svn.r-project.org/R/trunk@62998 00db46b3-68df-0310-9c12-caf00c1e9a41