Allow custom ping address

[ms1121]

• For those who dont want any contact with Google:
  https://duckduckgo.com/?q=google+cia
  https://www.google.com/search?q=google+cia

• Only need to detect if ethernet cable unplugged, ping local router instead
  https://www.macupdate.com/app/mac/14532/linkup

Network indicator turns grey when cable unplugged - source code
https://github.com/yujitach/MenuMeters
https://superuser.com/questions/411050/how-to-show-ethernet-status-in-the-os-x-menubar