h4h5tools

Make HDF5 Dataset names and attribute names safe.

NetCDF-4 has a strict rule regarding object names; it only accepts the following pattern:

  ([a-zA-Z0-9_]|{UTF8})([^\x00-\x1F\x7F/]|{UTF8})*

Besides, I believe the first character should not be a digit like most programming languages. This changelist changes the object name if it is not suitable.

This is applied only when netCDF-4 mode is enabled.