add deps directory

update inner include headers

sdk/include/plugin.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "session.h"
+#include <time.h>
+
+int plugin_session_event_register(int session_type, fn_session_event_callback cb, void *entry_arg);
+int plugin_session_timer_register(struct session *s, fn_session_timer cb, void *timer_arg, const struct timeval *timeout);
+
+int plugin_custom_session_event_register(const char *event_name, fn_session_event_callback cb, void *entry_arg);