Support ipv6 whitelisting

[webmaster777]

Having localhost automatically send to [::1] on my PC instead of 127.0.0.1, this took me quite some time to figure out the actual problem.

[PeeHaa]

The great @DaveRandom supplied me with https://gist.github.com/PeeHaa/3e7015617ee8cc32569d to implement ipv6 support.