RPC Cookie support for bitcoind rpc support

[jeffw387]

Looking through the main.rs file, I see support for RPC password auth, but cookie authentication seems to be the recommended "most secure" method of connection to bitcoind. Is there any chance of this being supported in the future?

[jeffw387]

I've just realized that the cookie file is user/password auth as well, so the main difference is how it's generated and accessed. So adding support for it would be pretty easy, I think. Would need to adjust the CLI interface, and allow for choosing a cookie file instead of supplying RPC user/password.