adding aliasing.txt to tutorial TOC

doc/tutorial/aliasing.txt

 
 .. _basictutaliasing:
 
-===============
-Memory Aliasing
-===============
+=======================================================
+Understanding Memory Aliasing for Speed and Correctness
+=======================================================
 
 The aggressive reuse of memory is one of the ways Theano makes code fast, and
 it's important for the correctness and speed of your program that you understand

doc/tutorial/index.txt

@@ -29,6 +29,7 @@ you out.
     loading_and_saving
     symbolic_graphs
     modes
+    aliasing
     using_gpu
     remarks
     debug_faq