Added Netgear support

As prompted by Nick Hilliard, code taken from Barry O'Donovan:

http://www.shrubbery.net/pipermail/rancid-discuss/2008-June/003128.html

Which was originally moulded into shape by Ed Ravin at:

http://www.shrubbery.net/pipermail/rancid-discuss/2008-April/003037.html