Add 'arp-ips'.

This script gets a list of ips in use on the local network. Duplicate
ARP responses are ignored.
Make 'nf' handle directories.

'nf' checked to make sure its arguments were existing files, but never
handled directories.
Add 'qnmap'.

This script encapsulates some common nmap scans. IP addresses or
hostnames are taken from stdin. Nmap's output is cleaned up to return
results like so: "ip:port".
Remove quotes in 'nf'.

These quotation marks are unnecessary.