[WIP] update mac configure script and add messaging about common port forwarding issue

update mac configure script and add messaging about port forwarding until we maybe use a better solution like how libtorrent does this, or RPC & UDP like this https://github.com/bmuller/rpcudp to avoid most port forwarding issues.
Perfect. :)

@gubatron What are your objections to performing `brew install python` blindly?