Add ARP spoof detection/mitigation functionality

[disconsis]

Let's be honest - DoS is annoying when you're not the one doing it.

And since I'm taking on (#6) detection avoidance anyway, for which I have to find out detection techniques in the first place, it'd be a shame to not implement them here.
Should set a nice back and forth.
I'll add techniques here as I find them.

• For starters, beat scapy's promiscping()

[disconsis]

Haven't had a look yet, but seems interesting: Detecting ARP Spoofing: An Active Technique
I'll add this as a task once I've had a good look.