Handbook Config and Tuning chapter cleanup

["Justin C. Sherrill" <justin@xxxxxxxxxxxxxxxxxx>]

http://forknibbler.com/handbook/config-tuning.html

I've removed the FreeBSD 5.0 refs, and cleaned up a few spots that don't
apply.  If someone familiar with ACPI can take a quick look, it would help
me out - I don't know if there's differences in 'our' ACPI from what's
there.