fix mac os safari bug && update doc

readme.md

@@ -40,7 +40,7 @@ gomitmproxy
 gomitmproxy -m 
 ```
 
-![fetch http](https://raw.githubusercontent.com/sheepbao/gomitmproxy/master/src/doc/goproxy.png)
+![fetch http](https://raw.githubusercontent.com/sheepbao/gomitmproxy/master/doc/goproxy.png)
 
 加 -m 参数，表示抓取http请求和响应
 
@@ -59,7 +59,7 @@ gomitmproxy -m
 ```
 然后浏览器设置代理，ip为localhost，端口为8080,即可实现科学上网
 
-![proxy](https://raw.githubusercontent.com/sheepbao/gomitmproxy/master/src/doc/proxy.png) 
+![proxy](https://raw.githubusercontent.com/sheepbao/gomitmproxy/master/doc/proxy.png) 
 
 ## 最后
 

src/vendor/mitm/mitm.go

@@ -269,7 +269,8 @@ func (hw *HandlerWrapper) Forward(resp http.ResponseWriter, req *http.Request, r
 
 	if req.Method == "CONNECT" {
 		b := []byte("HTTP/1.1 200 Connection Established\r\n" +
-			"Proxy-Agent: gomitmproxy/" + Version + "\r\n\r\n")
+			"Proxy-Agent: gomitmproxy/" + Version + "\r\n" +
+			"Content-Length: 0" + "\r\n\r\n")
 		_, err := connIn.Write(b)
 		if err != nil {
 			mylog.Println("Write Connect err:", err)