Determine cause of irregular crash in FSEventStreamCreate

[lucasvickers]

Likely due to an uninitialized variable / parameter in call to FSEventStreamCreate.

[lucasvickers]

Before FSEventStreamScheduleWithRunLoop is called, need to yield on the runloop to ensure the loop is ready.

    while( !mRunloop ) {
        std::this_thread::yield();
    }   
    FSEventStreamScheduleWithRunLoop( mFsevents, mRunloop, kCFRunLoopDefaultMode );