ptscotch - compiles into ptscotchDecomp. All thirdparty decompositionMethods
now moved out of decompositionMethods so add them explicitly to link line
for programs that need them (decomposePar, snappyHexMesh etc.)

- in preparation for adding an optional '-reconstruct' to a few utilities
  re-use as -lreconstruct library

- move related stuff there too
      src/decompositionMethods/decompositionMethods
      -> src/parallel/decompositionMethods

- added missing namespace qualifiers

which need this functionality.  Solvers will now check the correctness of the BCs on
read.