file in the experiment tbdata directory. This topo file is intended to
be used on the node to generate inputs to dijkstra and genhostsfile,
so that routes and /etc/hosts can be generated on the node, rather
then in tmcd, where it creates a huge bottleneck during experiment
startup of very large experiments (many 100s of nodes). This topo file is
slightly more rational then just dumping DB rows like we do from the RPC
server. For example:

	# nodes: vname,links
	lonely,link0:10.1.1.2
	node-1,lan0:10.1.2.2 link0:10.1.1.3
	node-2,lan0:10.1.2.3
	node-3,lan0:10.1.2.4
	# lans: vname,mask,cost
	lan0,255.255.255.0,1
	link0,255.255.255.0,1

Usage: gentopofile [-n] pid eid

The file is written as "topomap" in the current directory.  Use the
-n (impotent) option to dump the topofile to stdout rather writing to
the file.