hdf5_ep

Merge pull request #1860 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:map_api_merge to develop

* commit 'd95745235a468b17f697843adb3d0e54bd919893':
  Updated h5trav.c to emit output that doesn't require ddl changes for map support.
  Fixed Map API CMake option
  Renamed H5Mdelete_key to H5Mdelete and H5Mset to H5Mput.
  Added the map (H5M) API