RFC: Storage/Adding Disks rewrite

[Warren Block]

Many of the sections in the Storage chapter are very outdated.  Here is 
a rewrite of the Adding Disks section:

original version:
   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/disks-adding.html

new version:
   http://wonkity.com/~wblock/addingdisks/disks-adding.html
   diff: http://wonkity.com/~wblock/addingdisks/handbook-disks-adding.diff

Changes:

SATA rather than SCSI
GPT rather than MBR (and a link to Wikipedia GPT ref)
gpart rather than fdisk/bsdlabel
no sysinstall
no dedicated mode

It is much shorter than the original, and has far less distractions like 
the numerous problems of MBR.  Because it is a fairly big change, I'd 
like to get feedback on the various outrages it may commit in terms of 
completeness, justice, or, well, anything.

One possible addition as a new section would be complete setup of a new 
disk for the operating system, incorporating some of the content that is 
now at http://www.wonkity.com/~wblock/docs/html/disksetup.html .  I'd 
envision that as a mostly-commands section, and think it would follow 
this simple introduction well.