Change itkSimpleFastMutexLock to std::mutex

Change itkSimpleFastMutexLock to std::mutex
This is mandatory with ITK5 and c++11

The filters created an itk::Image<itk::SimpleFastMutexLock, dim> but this procedure is not possible with itk::Image<std::mutex, dim>
(cannot copy a mutex)
So I created a mutex alone and lock/unlock it when it is necessary