remain case sensitive of http header name and value,and expose headers as getter

websocket4j.server.WebSocket.handshake(Object... args)

String name = parts[0].toLowerCase();
String value = parts[1].toLowerCase();

->

String name = parts[0];
String value = parts[1];

and compare strings like name.equalsIgnoreCase("Upgrade")

and expose cookie,host,origin

private String cookie;

public String getCookie() {
 return cookie;
}