wcmd prog [args]
	connect to wily, set $WILYFD to be the file descriptor,
	then run 'prog'

rpc type [args]
	packs its arguments up in the wily message format
	(currently headed by a length field, and separated by nulls)
	and sends the message out on WILYFD, waits for the
	response (printing and discarding events), and
	prints the response on stdout.
