Change Refernece -> User Guide

doc/index.rst

 .. vim: set fileencoding=utf-8 :
 .. Andre Anjos <andre.anjos@idiap.ch>
 .. Mon  4 Nov 20:58:04 2013 CET
-.. 
+..
 .. Copyright (C) 2011-2013 Idiap Research Institute, Martigny, Switzerland
 
 ====================
@@ -12,8 +12,8 @@ This module contains base functionality from Bob bound to Python, available in
 the C++ counter-part ``bob::io``. It includes input and output operations to
 and from files.
 
-Reference
----------
+User Guide
+----------
 
 .. toctree::
    :maxdepth: 2