Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add a directory in /var/run to store ppp(8) command sockets.

PR: bin/29966
Approved by: brian
MFC after: 4

$Id$ -> $FreeBSD$

Add a rather complicated but impressive example of how
to implement multi-link ppp over more than one ISP with
the ability to lose ISPs without loss of connectivity.

It *requires* that you either have administrative access
to a machine that's already connected to the 'net or at
least know a really nice person that does.