Switch to std::atomic (available since Cpp-11)

The oneAPI-TBB implementation does not have an atomic implementation anymore.
The std implementation should be more than sufficient.

src/ITANUPFilterImpl.h

@@ -9,7 +9,7 @@
 
 #include <algorithm>
 #include <cassert>
-#include <tbb/atomic.h>
+#include <atomic>
 
 class NUPartition;
 
@@ -114,7 +114,7 @@ public:
 private:
 	ITANUPConvolutionImpl* m_pParent;
 	const NUPartition* m_pScheme;
-	tbb::atomic<int> m_iRefCount;
+	std::atomic<int> m_iRefCount;
 	std::vector<CUFilter*> m_vpSegments;
 	ITACriticalSection m_csReentrance;