* fix for #58
* add fixes for both retransmit and fuzz failure found
* fix infinite challenge ack due to RST+SYN+FIN corrupt packet in SYNRCV state
* fuzz: previous recovery ack path led to infinite transmit
* fuzz: calculate CRCs when fuzzing to reduce search space to non-CRC error cases
* add local fuzz corpus to tests
* add more cases to fuzz corpus
* tcp: bugfix for seq not in snd/rcv.wnd error
* accept dupe ACKs for window updates and prevent decrement of UNA
* add fixes for incorrect tcp functioning
* remove Conn.Available* methods in favor of Conn.Free* methods due to ambiguous name
* reduce heap allocations in tcp logging; omit use of AppendFloat which allocates a metric sh*tton
* debugheaplog: better heap statistic logging
* heap: use string for pcap.Frame.Protocol
* add potential to eliminate Flags.String heap alloc, remove incorrect HEAP comments
* add StackAsync.DebugErr and httpraw.SetBytes
* many heap alloc reductions and replacement of bytes.Equal with internal.BytesEqual
* 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