via the create-os directive in the NS file.
tbsetup/ir/handle_os.tcl - Do a valid check for the image given with
	set-node-os in the NS file, and propogate that information through
        to the IR file. Nothing is added to the DB.
tbsetup/mkexpdir - Add a tftpboot to the list of experiment directories. The
	tftpd daemon now allows kernels from /proj.
tbsetup/os_setup - Very hacky changes to allow for multiboot kernels. Read
	local images table and cross check against that for nodeos spec.
        Hardwire in "mb" as a special partition tag that says to not try
	and do too much with it. This should be changed to a DB check of
	some kind. On reboot, do not wait for these nodes to come alive since
	there is no way to determine if an oskit kernel (or any foreign)
	kernel is running.