Merge branch 'remove_mpi_type_hindexed_warning' into 'master'

feature/use MPI_Type_create_hindexed instead of MPI_Type_hindexed which is deprecated for MPI>=2

:)

See merge request !29
(cherry picked from commit dea4e7d0)

Signed-off-by: Steffen Müthing <muething@dune-project.org>