ENH: checkMesh: have -writeSets option

• checkMesh has option to write faceSets or (outside of) cellSets as sampledSurface format. It automatically reconstructs the set on the master and writes it to the postProcessing folder (as any sampledSurface). E.g.

  mpirun -np 6 checkMesh -allTopology -allGeometry -writeSets vtk -parallel

• fixed order writing of symmTensor in Ensight writers