Merge pull request #133 in HDF5VOL/daos-vol from ~SONGYULU/daos-vol:rayl/metadata_perf to master
* commit 'a113d1dd62b8ea2f164f8538280c7a89c7821b12':
Adding the link to the math library to h5daos_test_metadata_parallel alone.
Renamed h5daos_test_metadata.c to h5daos_test_metadata_parallel.c and added the link to the math library in CMake.
Added benchmarking for object opening functions and link functions.
Added benchmark for object closing (group, dataset, attribute, datatype, map, and file).
Added a program to benchmark metadata performance.
