Document the new feature from this PR.

doc/library/compile/index.txt

@@ -16,6 +16,7 @@
     shared
     function
     io
+    ops
     mode
     module
     debugmode

doc/library/compile/ops.txt

+==================================================
+:mod:`ops` --  Some Common Ops and extra Ops stuff
+==================================================
+
+.. automodule:: theano.compile.ops
+    :members:

theano/compile/ops.py

-"""This file contain auxiliary Ops, used during the compilation phase."""
+"""This file contain auxiliary Ops, used during the compilation phase
+and Ops building class (:class:`FromFunctionOp`) and decorator
+(:func:`as_op`) that help make new Ops more rapidly.
+
+"""
 import copy
 import warnings