bug#16402: 24.3.50; Document nadvice.el stuff in Elisp manual before Emacs 24.4

[Leo Liu]

On 2014-01-10 10:29 +0800, Andy Moreton wrote:
> As the author of nadvice.el, I would have thought that it was incumbent
> upon you to provide adequate documentation. A rationale to explain why
> the existing advice package needs changing would also be helpful.

In Stefan's defence this is him saying help me out. I am sure as the
maintainer of emacs he has plenty in his plate that some lower-priority
tasks may have to fall in others hands ;)

Leo