Recurse DNS names

One thing I've noticed when running the command `ffocus fb.com twitter.com` is that the module only blocks the sites I type as arguments. The problem with this is that aliases like `facebook.com` and `facebook.com.br` can still work as usual.

I don't know how to solve this issue yet, but one idea is to _"drill down"_ all dns names that points to a single IP, hence blocking all the accesses to the site.