hdf5

Merge pull request #1873 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:H5Pset_fapl_mpi to develop

* commit 'bd8da502cf5b763433e3c628a4043a4264529cec':
  Some refactoring prior to implementing new H5P MPI functions. * Macro cleanup and obvious warning fixes in parallel code. * Moved H5FD comm and info dup/free wrapper code to a new H5mpi.c file   and separated it to deal with each MPI type separately.