v0.19.0

1. Upgrade from a hyper request to a websocket connection
2. Upgrade all crate dependencies (openssl, hyper, etc.)
3. Make openssl an optional dependency
4. Use any Read/Write stream to make a websocket connection
5. Make clients with builder style API
6. Add / check protocols, extensions, headers, when upgrading connectin
7. Add / check protocols, extensions, headers, when building client
8. Docs for everything new
9. Much cleaner API overall