DAOS-VOL

Merge pull request #44 in HDF5VOL/daos-vol from ~JHENDERSON/daos-vol:master to master

* commit '246a61db91756b9b875a565d6f46e44805246144':
  Change H5_daos_iter_data_init routine to H5_DAOS_ITER_DATA_INIT macro
  Add temp. DAOS_OF_AKEY_HASHED and DAOS_OF_DKEY_HASHED for new DAOS API
  Implement H5Ocopy
  Implement H5Oincr/decr_refcount
  Implement H5Ovisit
  Implement H5Oexists_by_name
  Refactor H5Oget_info implementation into its own function
  Fix data corruption issue with partial edge chunks
  Fix issue with locating objects by path with leading './'