Change access on test fixtures to internal
TimedDictionary; IGuid and IKeyedItem linked
Add generic collections
Logger fixes

* Groups in BranchLoggers were not being propagated to the branch
  parent.

* FileLogSink wasn't printing newlines.

* GroupEntry was made convertible to/with JSON, and most of the
  LogEntry fields were added to it, for more granularity.
NamedCollection and SqlUtils