Initial IXP support. Very primitive; the IXP does not configure from
inside, but rather I do just enough to get the card booted (using Abhijeet's minicom/expect scripts, but with changes to support the configuration coming from tmcd. I also create a file of interface and routeadd directives, so that the network configures properly, but thats about it. Getting a more complete client side environment that includes perl and sshd for the arm will have to wait.