Rewrote the code to handle nested NSManagedObjectContext's. This can now handle the case of a NSPrivateQueueConcurrencyType context having an NSMainQueueConcurrencyType context as parent.
Fixed validation of NSMainQueueConcurrencyType
Fixed false positive caused by Core Data deallocating NSManagedObjects on a background queue
More robust setting of the concurrency identifier of NSManagedObjectContext's by setting at at init time.
Fixed concurrency validation when nested contexts are used and added a testsuite.
Initial release.