hdf5_der

Merge pull request #200 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:name_macros to develop

Merged naming check improvement in function enter macros.

* commit '441c8ea43ab6a6559d1f167bdfbbaf3720621804':
  Added text to the function check macros so that a more helpful error message is emitted when there is a problem.