modernize the section on BPF (modern BSDs have BPF built in and clone
BPF devices, so no configuration should be necessary; we can add back
the old instructions if people using older BSDs run into problems), and
add information on making BPF devices available to non-root users.
svn path=/trunk/; revision=18880
they have LF at the end of the line on UN*X and CR/LF on Windows;
hopefully this means that if a CR/LF version is checked in on Windows,
the CRs will be stripped so that they show up only when checked out on
Windows, not on UN*X.
svn path=/trunk/; revision=11400
Gerald Combs