add provided thread level

Link: https://github.com/GeneAssembly/biosal/issues/47
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
add communication threads in a node

This feature needs MPI_THREAD_MULTIPLE which is not available
in most Linux distribution mpich packages.

Suggested-by: Fangfang Xia <fangfang@anl.gov>
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>