Added full path to date, ifconfig, ifup and ifdown

[AndrewFromMelbourne]

Hi Kevin, Thanks for publishing this script. I am using it on my RPi and it works very well. To get it working as a crontab entry on my system (Debian Wheezy) I needed to put the full path to date, ifconfig, ifup and ifdown. I though I would send you a pull request (if you find the changes useful). Andrew

[ghost]

Thank you so much for this change! You saved my day! Got it working on the RPi. I'd never have gotten the idea to add full paths-