Merge branch 't' into t2

* t:
  .
  .

go/NOTES

@@ -52,7 +52,7 @@ LastIDs			PM -> S		S -> PM
 
 PartitionTable		PM -> S		S -> PM
 NotifyPartitionTable	PM -> S, C
-PartitionChanges	PM -> S, C		// subset of NotifyPartitionTable (?)
+PartitionChanges	PM -> S, C		// δ(partTab)
 
 StartOperation		PM -> S
 StopOperation		PM -> S

go/zodb/pydata.go

@@ -69,7 +69,7 @@ func encodePyData(pyclass pickle.Class, pystate interface{}) PyData {
 	p := pickle.NewEncoderWithConfig(buf, &pickle.EncoderConfig{
 		// allow pristine python2 to decode the pickle.
 		// TODO 2 -> 3 since ZODB5 switched to it and uses zodbpickle.
-		Protocol:      2,	// XXX -> 3?
+		Protocol:      2,
 		PersistentRef: persistentRef,
 	})