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_common.h

@@ -0,0 +1,82 @@
+#pragma once
+
+extern "C"
+{
+#include <sys/queue.h>
+}
+
+#include <tfe_http.h>
+#include <http_parser.h>
+
+struct http_plugin
+{
+};
+
+TAILQ_HEAD(hs_private_list, http_session_private);
+struct http_session_private
+{
+	struct tfe_http_session hs_public;
+	TAILQ_ENTRY(http_session_private) next;
+	struct http_connection_private * hc_private;
+};
+
+struct http_connection_private
+{
+	/* ADDRESS */
+	struct tfe_stream_addr * layer_addr;
+	/* SESSION LIST, REQUEST-RESPONSE PAIRS */
+	struct hs_private_list hs_private_list;
+	/* IS PREEMPTED */
+	unsigned int is_preempted;
+	/* SESSION ID COUNTER */
+	unsigned int session_id_counter;
+};
+
+struct http_half_private
+{
+	/* PUBLIC STRUCTURE */
+	struct tfe_http_half hf_public;
+	/* SESSION OF THIS REQUEST/RESPONSE */
+	struct http_session_private * session;
+	/* HTTP PARSER */
+	struct http_parser * parse_object;
+	/* HTTP PARSER SETTING */
+	struct http_parser_settings * parse_settings;
+	/* CURSOR RELATED TO DELAYED DATA */
+	size_t parse_cursor;
+	/* HTTP PARSER'S ERRNO */
+	enum http_errno parse_errno;
+
+	/* UNDERLAY BUFFER */
+	int method_or_status;
+	short major;
+	short minor;
+
+	struct evbuffer * evbuf_uri;
+	char * underlay_uri;
+	char * underlay_url;
+
+	struct evbuffer * evbuf_header_field;
+	struct evbuffer * evbuf_header_value;
+	struct evbuffer * evbuf_body;
+
+	/* STATUS */
+	bool finished;
+};
+
+static inline struct http_half_private * to_hf_request_private(struct http_session_private * hs_private)
+{
+	struct tfe_http_half * hf_public = hs_private->hs_public.req;
+	return container_of(hf_public, struct http_half_private, hf_public);
+}
+
+static inline struct http_half_private * to_hf_response_private(struct http_session_private * hs_private)
+{
+	struct tfe_http_half * hf_public = hs_private->hs_public.resp;
+	return container_of(hf_public, struct http_half_private, hf_public);
+}
+
+static inline struct tfe_http_half * to_hf_public(struct http_half_private * hf_private)
+{
+	return &hf_private->hf_public;
+}