Only wake up EngineWorkerScheduler if there are worker threads to be started.
Add time tracking and events to stats. Keep a long-running log of events.
Add support for writing a timeline on exit.
Make Trace() use StatsManager events.

* Use PerformanceTimer instead of QTime.
* Default stdout to off and time to on.
Some VSyncThread cleanups.
Add event tracing in many useful places.
Misc. cleanups.
Use libsndfile in normalized float mode. Fixes Bug #1265727.