ENH: use Zero when zero-initializing types

- makes the intent clearer and avoids the need for additional
  constructor casting. Eg,

      labelList(10, Zero)    vs.  labelList(10, 0)
      scalarField(10, Zero)  vs.  scalarField(10, scalar(0))
      vectorField(10, Zero)  vs.  vectorField(10, vector::zero)

src/meshTools/AMIInterpolation/AMIInterpolation/AMIInterpolationParallelOps.C

@@ -41,7 +41,7 @@ Foam::label Foam::AMIInterpolation<SourcePatch, TargetPatch>::calcDistribution
 
     if (Pstream::parRun())
     {
-        List<label> facesPresentOnProc(Pstream::nProcs(), 0);
+        labelList facesPresentOnProc(Pstream::nProcs(), Zero);
         if ((srcPatch.size() > 0) || (tgtPatch.size() > 0))
         {
             facesPresentOnProc[Pstream::myProcNo()] = 1;

src/meshTools/AMIInterpolation/AMIInterpolation/AMIMethod/directAMI/directAMI.C

@@ -257,7 +257,7 @@ void Foam::directAMI<SourcePatch, TargetPatch>::calculate
 
     // list to keep track of whether src face can be mapped
     // 1 = mapped, 0 = untested, -1 = cannot map
-    labelList mapFlag(srcAddr.size(), 0);
+    labelList mapFlag(srcAddr.size(), Zero);
 
     label nTested = 0;
     DynamicList<label> nonOverlapFaces;

src/meshTools/cellQuality/cellQuality.C

@@ -49,7 +49,7 @@ Foam::tmp<Foam::scalarField> Foam::cellQuality::nonOrthogonality() const
 
     scalarField& result = tresult.ref();
 
-    scalarField sumArea(mesh_.nCells(), 0.0);
+    scalarField sumArea(mesh_.nCells(), Zero);
 
     const vectorField& centres = mesh_.cellCentres();
     const vectorField& areas = mesh_.faceAreas();
@@ -110,7 +110,7 @@ Foam::tmp<Foam::scalarField> Foam::cellQuality::skewness() const
     );
     scalarField& result = tresult.ref();
 
-    scalarField sumArea(mesh_.nCells(), 0.0);
+    scalarField sumArea(mesh_.nCells(), Zero);
 
     const vectorField& cellCtrs = mesh_.cellCentres();
     const vectorField& faceCtrs = mesh_.faceCentres();

src/meshTools/edgeMesh/extendedEdgeMesh/extendedEdgeMesh.C

@@ -1864,7 +1864,7 @@ bool Foam::extendedEdgeMesh::mergePointsAndSort
     }
 
     // Re-classify merged points
-    labelList nPoints(nNewPoints, 0);
+    labelList nPoints(nNewPoints, Zero);
     forAll(oldToMerged, oldPointI)
     {
         nPoints[oldToMerged[oldPointI]]++;

src/meshTools/momentOfInertia/momentOfInertia.C

@@ -80,7 +80,7 @@ void Foam::momentOfInertia::massPropertiesSolid
     const scalar r120 = 1.0/120.0;
 
     // order:  1, x, y, z, x^2, y^2, z^2, xy, yz, zx
-    scalarField integrals(10, 0.0);
+    scalarField integrals(10, Zero);
 
     forAll(triFaces, i)
     {

src/meshTools/polyMeshZipUpCells/polyMeshZipUpCells.C

@@ -84,7 +84,7 @@ bool Foam::polyMeshZipUpCells(polyMesh& mesh)
 
             // Find the edges used only once in the cell
 
-            labelList edgeUsage(cellEdges.size(), 0);
+            labelList edgeUsage(cellEdges.size(), Zero);
 
             forAll(curFaces, facei)
             {
@@ -177,7 +177,7 @@ bool Foam::polyMeshZipUpCells(polyMesh& mesh)
             // points marked twice are internal to edge; those marked more than
             // twice are corners
 
-            labelList pointUsage(cellPoints.size(), 0);
+            labelList pointUsage(cellPoints.size(), Zero);
 
             forAll(singleEdges, edgeI)
             {
@@ -737,8 +737,8 @@ bool Foam::polyMeshZipUpCells(polyMesh& mesh)
         // (edge, point) addressing.
 
         // Collect the patch sizes
-        labelList patchSizes(bMesh.size(), 0);
-        labelList patchStarts(bMesh.size(), 0);
+        labelList patchSizes(bMesh.size(), Zero);
+        labelList patchStarts(bMesh.size(), Zero);
 
         forAll(bMesh, patchi)
         {

src/meshTools/processorLOD/box/box.C

@@ -444,7 +444,7 @@ Foam::autoPtr<Foam::mapDistribute> Foam::processorLODs::box::createMap
     {
         // Per processor refinement info
         List<labelList> refineFlags(Pstream::nProcs());
-        labelList nElems(Pstream::nProcs(), 0);
+        labelList nElems(Pstream::nProcs(), Zero);
 
         // Assess how many target elements intersect the source bounding boxes
         // and use the info to flag how the source boxes should be refined

src/meshTools/searchableSurfaces/searchableSurfaceCollection/searchableSurfaceCollection.C

@@ -121,7 +121,7 @@ void Foam::searchableSurfaceCollection::sortHits
 ) const
 {
     // Count hits per surface.
-    labelList nHits(subGeom_.size(), 0);
+    labelList nHits(subGeom_.size(), Zero);
 
     forAll(info, pointi)
     {

src/meshTools/triSurface/booleanOps/intersectedSurface/edgeSurface.C

@@ -76,7 +76,7 @@ void Foam::edgeSurface::calcPointEdges()
 {
     pointEdges_.setSize(points_.size());
 
-    labelList pointNEdges(points_.size(), 0);
+    labelList pointNEdges(points_.size(), Zero);
 
     forAll(edges_, edgeI)
     {

src/meshTools/triSurface/booleanOps/intersectedSurface/intersectedSurface.C

@@ -1102,7 +1102,7 @@ Foam::intersectedSurface::intersectedSurface
     DynamicList<labelledTri> newTris(eSurf.edges().size()/2);
 
     // Start in newTris for decomposed face.
-    labelList startTrii(surf.size(), 0);
+    labelList startTrii(surf.size(), Zero);
 
     forAll(surf, facei)
     {

src/meshTools/triSurface/triSurfaceSearch/triSurfaceRegionSearch.C

@@ -92,7 +92,7 @@ Foam::triSurfaceRegionSearch::treeByRegion() const
             regionsAddressing[regionI] = labelList(regionSizes[regionI], -1);
         }
 
-        labelList nFacesInRegions(nRegions, 0);
+        labelList nFacesInRegions(nRegions, Zero);
 
         forAll(surface(), fI)
         {

src/meshTools/triSurface/triSurfaceTools/triSurfaceCurvature.C

@@ -160,7 +160,7 @@ Foam::triSurfaceTools::curvatures
         symmTensor2D::zero
     );
 
-    scalarList accumulatedWeights(points.size(), 0.0);
+    scalarList accumulatedWeights(points.size(), Zero);
 
     forAll(surf, fI)
     {