link official doc from rtfdwq

docs/source/conf.py

@@ -23,7 +23,7 b' if ON_RTD:'
     # Mock the presence of matplotlib, which we don't have on RTD
     # see
     # http://read-the-docs.readthedocs.org/en/latest/faq.html
-
+    tags.add('rtd')
     class Mock(object):
         def __init__(self, *args, **kwargs):
             pass

docs/source/index.txt

@@ -7,7 +7,13 b' IPython Documentation'
    :Release: |release|
    :Date: |today|
 
-Welcome to the official IPython documentation.
+.. only:: not rtd
+
+    Welcome to the official IPython documentation.
+
+.. only:: rtd
+
+    This is a partial copy of IPython documentation, please visit `IPython official documentation <http://ipython.org/documentation.html>`_.
 
 Contents
 ========