This program is based on mping by mhusmann. It has been almost entirely re-written as I have learned more about Go and its concurrency patterns.
Usage: ipscan [-quv] [-n value] [-t value] startIP endIP
-n, --count=value max number of pings per target
-q, --quiet only display host data
-t, --rtt=value max RTT for each ping
-u, --udp use UDP instead of ICMP
-v, --debug print additional messages
startIP, endIP endpoints of scan (inclusive)