完成HTTP解析请求侧解析基本流程

* 集成HTTP Parser，解析HTTP请求侧数据；
* 增加tfe_http.h中请求方法、应答状态的常量定义
* 变更tfe_http.h中HTTP头部标准定义，去掉非头部字段，增加TFE前缀避免冲突。

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

@@ -0,0 +1,18 @@
+#pragma once
+
+struct http_half_private * hf_private_create(tfe_http_direction ht_dir, short major, short minor);
+void hf_private_destory(struct http_half_private * hf_private);
+
+/** Parse the raw tcp input for HTTP half structure
+ * @param hf_private
+ * 		hf_private handler.
+ * @param data
+ * 		raw tcp data, used in the stream's callback.
+ * @param len
+ * 		raw tcp data length.
+ * @return
+ * 		0 for need more data,
+ * 		1 for reach the boundary, need to call http business callbacks,
+ * 		-1 for error.
+ */
+int hf_private_parse(struct http_half_private * hf_private, const unsigned char * data, size_t len);