release 4.38

NOTE The below mentioned wire protocol change is backwards-incompatible. You have to update all your pyro libraries on clients and servers. (And Pyrolite libraries if you use them too)

• wire protocol version changed to 48 (new connection logic).
• changed the initial connection handshake protocol. Proxy and daemon now perform a handshake by exchanging data.
  You can set your own data on the proxy attribute _pyroHandshake. You can override a proxy method _pyroValidateHandshake
  and a daemon method validateHandshake to customize/validate the connection setup.
• drastically reduced the overhead of creating a new proxy connection by piggybacking the metadata on the
  connection response (this avoids a separate remote call to get_metadata). New proxy connections are ~50% faster.
• added Daemon.clientDisconnect() as a hook for when clients disconnect (Daemon.validateHandshake can
  be used as the hook to handle new connections)
• you can now register a class on the Daemon instead of an object, and define instancing strategy: singleton, session, percall
• you can provide an optional factory method to create instances of your pyro server class when needed according to the instancing_strategy
• added handshake, instancemode and usersession examples
• added distributed-computing2 example
• added messagebus example
• fixed callcontext example daemon to actually return a custom annotation
• fixed benchmark/connections example
• httpgateway recognises X-Pyro-Correlation-Id http header on requests
• new mailing list address ([email protected]). Bye bye Sourceforge.