Add more chaining to RedisClient

I was annoyed about `#select()` and `#auth()` so I fixed it for almost everything on RedisClient. Avoided a few methods that return something. None of these ever did:

    install_stream_listeners
    initialize_retry_vars
    unref
    flush_and_error
    on_error
    do_auth
    on_connect
    on_ready
    ready_check
    send_offline_queue
    connection_gone
    on_data
    return_error
    return_reply
    pub_sub_command
    select
    auth
    eval