h4h5tools

HFRHFVTOOLS-11, for unlimited dimension, the dimension size should be the current dimension size with the maximum dimension size to be H5S_UNLIMITED. Fix this issue. Also fix a C string operation issue, use HDF4 SDS type for the pure dimension datatype. At last, improve error handling a little bit. The current revision can convert CERES edition 4 test file to HDF5 that can be correctly accessed by both Panoply and ncdump.