Multiple routing table support commited

I have committed the base of teh Multi-routing-table support.
I am current;y waiting for it to loop back to me before a final
make universe test, but I think it should be ok.
if you do nothing you should not see any difference.

for a description  of what and how, look at:

http://perforce.freebsd.org/fileViewer.cgi?FSPC=//depot/user/julian/routing/plan.txt

to compile it into a kernel you need

  options ROUTETABLES=N where N is from 1 to 16

leaving it out, or setting it to 1 will have the effect of
creating a kernel that should behave as it did prior to this
commit.

In this work a kernel routing table is
referred to as  a 'fib'  (Forwarding Information Base).
I was informed by various routing people during this work
that this is the new-fangled correct name for an in kernel
routing(forwarding) table.

for more information see

setfib(1) and setfib(2)



This code, backported to 6.3 is running on Ironport appliances
and Cisco/Ironport has graciously allowed it to be given back.

julian