Replacing nwipe with shred

[lawrencesystems]

Replacing nwipe with shred command instead. On the raspberry pi nwipe will randomly lock up when shredding multiple hard drives at the same time.

[pgporada]

Thanks for letting me know! I believe my plan of action is going to be specifying the wiping utility in the config file. If I do that, the flags for that utility would need to be defined as well. Regardless, the config file will have an example.

[pgporada]

Done!