[R] how to rotate elements in a vector and points in a plane

[Ondřej Mikula]

Dear R-helpers,

I need two simple functions, I guess they exist in R, but I am unable
to find them.
The first function should cyclically rotate elements in a vector.
("guyrot" in the package "wavethresh" should do it, but there's some
problem with its loading)
The second function should rotate points in 2D by a given angle (about
the defined point).

Thanks for any advice
Ondra Mikula