BUG: Update LabelOverlapMeasures internal class

Use rule of zero, and change to SizeValue type for accumulant type.

Author: blowekamp

Modules/Filtering/ImageStatistics/include/itkLabelOverlapMeasuresImageFilter.h

@@ -80,39 +80,14 @@ class ITK_TEMPLATE_EXPORT LabelOverlapMeasuresImageFilter : public ImageSink<TLa
   class LabelSetMeasures
   {
   public:
-    // default constructor
-    LabelSetMeasures()
-    {
-      m_Source = 0;
-      m_Target = 0;
-      m_Union = 0;
-      m_Intersection = 0;
-      m_SourceComplement = 0;
-      m_TargetComplement = 0;
-    }
-
-    // added for completeness
-    LabelSetMeasures &
-    operator=(const LabelSetMeasures & l)
-    {
-      if (this != &l)
-      {
-        m_Source = l.m_Source;
-        m_Target = l.m_Target;
-        m_Union = l.m_Union;
-        m_Intersection = l.m_Intersection;
-        m_SourceComplement = l.m_SourceComplement;
-        m_TargetComplement = l.m_TargetComplement;
-      }
-      return *this;
-    }
-
-    unsigned long m_Source;
-    unsigned long m_Target;
-    unsigned long m_Union;
-    unsigned long m_Intersection;
-    unsigned long m_SourceComplement;
-    unsigned long m_TargetComplement;
+    // default constructor/copy/move etc...
+
+    SizeValueType m_Source{ 0 };
+    SizeValueType m_Target{ 0 };
+    SizeValueType m_Union{ 0 };
+    SizeValueType m_Intersection{ 0 };
+    SizeValueType m_SourceComplement{ 0 };
+    SizeValueType m_TargetComplement{ 0 };
   };
 
   /** Type of the map used to store data per label */