CFWrapper-alike for dispatch_object_t's.
Replace Mach semaphore with a GCD semaphore.
Deploy to 10.9, fix resulting deprecation.
Dispatch queue and timer wrapper class.
Move AudioPlayer collection thread to GCD.
Make queue signalling respect DispatchSync behavior.
Replace expensive mutex with queue
Use optimized iterator in AudioMetadata loop
Ape Apple's int64_t string parser