Fixed all H2 headings

Before, H2 fomratting was not consistent.
Now, all H2 headings use over/under asterisks.

docs/scenarios/network.rst

@@ -5,8 +5,10 @@ Networking
 
 .. image:: /_static/photos/34151833832_6bdfd930af_k_d.jpg
 
+
+*******
 Twisted
--------
+*******
 
 `Twisted <http://twistedmatrix.com/trac/>`_ is an event-driven networking
 engine. It can be used to build applications around many different networking
@@ -14,8 +16,10 @@ protocols, including http servers and clients, applications using SMTP, POP3,
 IMAP or SSH protocols, instant messaging
 and `much more <http://twistedmatrix.com/trac/wiki/Documentation>`_.
 
+
+*****
 PyZMQ
------
+*****
 
 `PyZMQ <http://zeromq.github.com/pyzmq/>`_ is the Python binding for
 `ZeroMQ <http://www.zeromq.org/>`_, which is a high-performance asynchronous
@@ -32,8 +36,10 @@ message queuing without a message broker. The basic patterns for this are:
 
 For a quick start, read the `ZeroMQ guide <http://zguide.zeromq.org/page:all>`_.
 
+
+******
 gevent
-------
+******
 
 `gevent <http://www.gevent.org/>`_ is a coroutine-based Python networking
 library that uses greenlets to provide a high-level synchronous API on top of