clean the code

source/network/Main.cpp

 /* NiuTrans.Tensor - an open-source tensor library
- * Copyright (C) 2017, Natural Language Processing Lab, Northestern University.
+ * Copyright (C) 2018, Natural Language Processing Lab, Northestern University.
  * All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -16,11 +16,7 @@
  */
 
 /*
- *
- * This is the entrance of the low-level tensor library : NiuTrans.Tensor
- *
- * $Created by: XIAO Tong (xiaotong@mail.neu.edu.cn) 2015-12-14
- *
+ * $Created by: XIAO Tong (xiaotong@mail.neu.edu.cn) 2018-07-10
  */
 
 #include <stdio.h>