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/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.C

@@ -550,7 +550,7 @@ Foam::distributedTriSurfaceMesh::calcLocalQueries
     // cheap we do a multi-pass algorithm to save some memory temporarily.
 
     // 1. Count
-    labelList nSend(Pstream::nProcs(), 0);
+    labelList nSend(Pstream::nProcs(), Zero);
 
     forAll(info, i)
     {