docs: update doxygen configuration

Most notably:
 - use relative paths in file list instead of file name only
 - enable sorting of brief descriptions of class members
 - show one enum value per line

refs #4163

Change-Id: Ib08601bc90f6eeb4e8754ed4335a447d5d0cc26c
diff --git a/README-dev.md b/README-dev.md
index bb16427..156c649 100644
--- a/README-dev.md
+++ b/README-dev.md
@@ -11,7 +11,7 @@
 Include the following license boilerplate into all `.hpp` and `.cpp` files:
 
     /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-    /**
+    /*
      * Copyright (c) [Year(s)],  [Copyright Holder(s)].
      *
      * This file is part of NFD (Named Data Networking Forwarding Daemon).