Merge pull request #4017 from fvisin/fix_tutorial

Replace deleted pages with link to new pages

Merge pull request #4017 from fvisin/fix_tutorial
b46e24dc · Frédéric Bastien · 51b840e1 · 299f0e2d · b46e24dc · b46e24dc
--- a/doc/tutorial/extending_theano.txt
+++ b/doc/tutorial/extending_theano.txt
+:orphan:
+This page has been moved. Please refer to: :ref:`extending_theano`. 
--- a/doc/tutorial/extending_theano_c.txt
+++ b/doc/tutorial/extending_theano_c.txt
+:orphan:
+This page has been moved. Please refer to: :ref:`extending_theano_c`. 
--- a/doc/tutorial/symbolic_graphs.txt
+++ b/doc/tutorial/symbolic_graphs.txt
+:orphan:
+This page has been moved. Please refer to: :ref:`graphstructures`.