adding new p function for easy ping

What do you think of this new ping command?
Without argument it ping to 8.8.8.8 (google dns = usefull for connection test).
It completes the given parameter with the local IP prefix (192.168.1.). This allow to do a simple ping 3.18 to ping 192.168.3.18 (typing 192.168. drives me crazy -_-)
I disabled the "p" alias.