Add an option to whitelist networks

This warning is possible for anything socket trying to connect to a localhost address.

WARNING torsocks[12360]: [connect] Connection to a local address are denied since it might be a TCP DNS query to a local DNS server. Rejecting it for safety reasons. (in tsocks_connect() at connect.c:177)

We should implement a whitelist mechanism so the user can tell which local network is allowed such as localhost.