/**
  * @mainpage Aurum Protocol
  * @section main_intro Introduction
  * this is quick introduction
  * @li @ref libaurum
  * @li @ref protocol
  * @li @ref aurum-bootstrap
  * @section main_architecture Overall Architecture
  * this is breif overall architecture
  * @section main_tutorial Tutorial
  * this shows you how to use aurum
  * @subsection main_tutorial_step1 Step1
  * tutorial step 1
  * @subsection main_tutorial_step2 Step2
  * tutorial step 2
  * @subsection main_tutorial_step3 Step3
  * tutorial step 3
  * @subsection main_tutorial_step4 Step4
  * tutorial step 4
  */