- Added Doxygen source code documentation parts (donated by Fox-IT)

diff --git a/include/polarssl/debug.h b/include/polarssl/debug.h
index 43634b7..c6f7406 100644
--- a/include/polarssl/debug.h
+++ b/include/polarssl/debug.h
@@ -1,6 +1,8 @@
 /**
  * \file debug.h
  *
+ * \brief Debug functions
+ *
  *  Copyright (C) 2006-2010, Brainspark B.V.
  *
  *  This file is part of PolarSSL (http://www.polarssl.org)