Simple thread-based tcp proxy

Simple tcp proxy that opens 2 threads per connection

Example usage:

• Forward ports 80 and 443 to 216.58.212.110 ./tcp_proxy -i 216.58.212.110
• Forward ports 23 and 80 to 192.168.1.5 ./tcp_proxy -i 192.168.1.5 -h 23,80
• Forward port 80 to netflix.com ./tcp_proxy -h netflix.com -h 80