Merge "make new \'referenceonly\' docs build the default for offline docs. add preview codename and version number HDF variables for generated docs." into nyc-dev am: 5904f246ca
am: bdf6f6b89a

* commit 'bdf6f6b89a715f3c0534ffd672460b955875575e':
  make new 'referenceonly' docs build the default for offline docs. add preview codename and version number HDF variables for generated docs.