Allow /nn specifications in the `add' command.
Suggested by: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
It's now possible to
add myaddr 127.0.0.1 (add myaddr 255.255.255.255 127.0.0.1) add hisaddr/24 hisaddr (add hisaddr 255.255.255.0 hisaddr) add 0 hisaddr (add 0 0 hisaddr) add default hisaddr (add 0 0 hisaddr)