Client handshake does not support Authorization header

[michael-hibachi-xyz]

Ratchet has been a great find – it's the only Rust websocket library I could find that supports permessage-deflate.

However, it does not seem to support passing an authorization header during the handshake – a pretty essential feature for any production application.

Without this feature, we sadly cannot use it for our use case.

[michael-hibachi-xyz]

I put up a change to support this. @SirCipher, I would greatly appreciate if you could take a look :)