Make special-case exemptions for blocking 0.0.0.0 and 255.255.255.255

[EvanAnderson]

Make sure the script can't block 0.0.0.0 and 255.255.255.255.

That shouldn't ever happen, since the only way the script gets IP addresses is from IPs that failed logons from the Event Log, but it's not a big deal to special-case except them anyway.

[greatquux]

This actually just happened to me on a production server. Knocked everyone out. I will add a simple check to avoid these being blocked.

[greatquux]

I also had to add a special case exemption for 127.0.0.1 as I noticed this IP being added too. Of course any of these can be added to the simple Whitelist but it's best to hardcode these IPs as they can't be properly unblocked and server must be rebooted to fix network communications.