doc cleanup checkovers

[Justin C. Sherrill]

For anyone who has a spare moment:  I've made it most of the way through the
Handbook conversion, but there's a few spots I'd like to have another set
of eyes looking.

http://forknibbler.com/handbook/vinum-root.html

I merged together some parts of the Vinum docs that were split between
FreeBSD 4.x and 5.x sections; if someone vaguely familiar with Vinum can
check for readability/sense, I'd appreciate it.

http://forknibbler.com/handbook/desktop-browsers.html

This is an easy one: are you running a web browser with Flash or even Java
enabled?  How'd you do it?  The current description for setting that up in
the handbook is out of date.

The rest of the conversion is pretty straightforward; fix &os; references
and remove/merge 5.x-specific data.  I only have the last two chapters to
go.