集成GZIP压缩模块，支持对GZIP压缩的应答执行替换业务，并增加了单元测试用例。

plugin/protocol/http/include/internal/http_half.h

@@ -65,8 +65,10 @@ struct http_half_private
 	char * url_storage;
 
 	/* Content-Encoding */
+	uint16_t accept_content_encoding;
 	uint16_t content_encoding;
 	struct hf_content_uncompress * cv_uncompress_object;
+	struct hf_content_compress * cv_compress_object;
 
 	/* Header Parser */
 	struct evbuffer * evbuf_header_field;