* begin adding icmp client
* rely on anon structs
* add tests
* tests passing
* icmp fleshed out
* rework icmp to include ip addr
* rename StackAsync.Demux/Encapsulate to RecvEthernet and SendEthernet
* remove legacy unreachable TCP tests
* remove uses of deprecated internet.StackNode in preference of lneto.StackNode
* documentation
* rename methods to signal no I/O happening
* 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