We had already implemented Read, Write, and Close. Pass RemoteAddr,
LocalAddr, SetReadDeadline, and SetWriteDeadline through to the
underlying *websocket.Conn. Implement SetDeadline by calling both
SetReadDeadline and SetWriteDeadline.
https://bugs.torproject.org/33144
Rename websocketconn.WebSocketConn to websocketconn.Conn, and
websocketconn.NewWebSocketConn to websocketconn.New
Following the guidelines at
https://blog.golang.org/package-names#TOC_3%2e