* do not rely on unspecified Go behaviour; fix TCP ring buffer bug
* even more stricter error handling on tcp connections
* stricter lock copying in tcp.Conn, even though likely not a problem
* add listener and tcp pool logging
* forgot reqAddr unused
* add logging to TCPConn and friends
* begin reviewing TCP listener
* begin adding listener tests
* adding TestExchange implementation
* split out legacy and Step tests
* move listener to tcp package
* fix up tcp tests taking very long
* add xnet.TCPPool and work on TCPPool semantics
* xnet: TCPPool only accepts established connections
* xnet: getting to bottom of panic in xnet.Listener
* xnet: improve listener tests
* fix several data races in testing fixtures
* fix more synchronization things in listener test
* finalize tcplistener test
Pat Whittingslow