Documentation enhancements.

   be used without Gevent or Threading.

 * **Multiplexed:** sjRpc can run many "protocols" on the same connection,

   read more about protocols in `Multiplexing & protocols`_ section.

 * **Fallback mode:** for compatibility with olders sjRpc.

Multiplexing & protocols

 * **Tunnel:** protocol which allow to tunnel a socket through the sjRpc

   connection.

.. note::

   A Rpc protocol is automatically created and binded to label 0 when a

   :class:`RpcConnection` class is instantiated. This can't be changed or

   removed.

To register new protocols, you can use the :meth:`register_protocol` on

:class:`RpcConnection` instances, like this::

  >>> from sjrpc.core.protocols import RpcProtocol, TunnelProtocol

  >>> my_tunnel = myconn.register_protocol(1, TunnelProtocol)

  do the same on other side, then

  >>> mytunnel.send('ehlo !!')

  >>> anwser = mytunnel.recv()

You can also use shortcuts::

  >>> my_tunnel = myconn.create_tunnel(label=12)

  or

  >>> my_tunnel = myconn.create_tunnel() # Bind to the first free label

The same shortcut is available for rpc with :meth:`create_rpc`.

Default rpc, aka Rpc0

---------------------

    Function handler decorator -- the function is a pure fonction, caller will

    not pass :class:`RpcConnection` object as first call parameters.

    .. note::

    .. deprecated:: 14

       This decorator is useless since the default behavior have change. You

       can use :func:`pass_connection` decorator to do the opposite.