* fix a possible deadlock in AsyncJobQueue
drainAndExit() could get stuck because it waited for the job
queue to be empty, but that was not signaled.
in fact, drainAndExit() didn't need to do that.
* Improvements to FrameInfo
- return the GPU Complete timestamp
- return the app VSYNC timestamp
- works TimerQueries are not supported
The VSYNC time is just a convenience as it is the same value
provided by the application during Renderer::beginFrame() or via
Renderer::setVsyncTime().
* new utility AsyncJobQueue
this is a very simple job queue, it spawns a thread and runs the jobs
pushed to the queue in sequence.
* use AsyncJobQueue in OpenGLTimerQuery
Mathias Agopian