hdf5_chunking_query_bmr

Merge pull request #519 in HDFFV/hdf5 from ~BYRN/hdf5_adb:develop to develop

* commit '71637634ac96b6167b384ebb461ce3b9ea66b4f8':
  HDFFV-9995 Clarify help text
  HDFFV-10128 Fixed string length with no null fixed