adding sync latency tests to CAF benchmarks
add command-line argment in caf tests to specify partner pairs
incorporating shmem_ptr into shmem tests

To disable shmem_ptr usage, remove -DUSE_SHMEM_PTR in makefile
minor update to README
add command-line option for other tests to specify partner pairs
removing redundant num_active_nodes variable
updating README
minor update to README file
create a separe directory for MPI (non-PGAS)