h4h5tools

 Some HDF4 files have a vgroup name that this bigger than VGNAMELENMAX, the maximum size of the old HDF4 library allows. The h4toh5 conversion tool still uses VGNAMELENMAX, so it causes memory buffer overrun for some cases.
The current fix will use the new HDF4 APIs(in hdf4.2.5) Vgetnamelen and Vgetclassnamelen to obtain the vgroup name and class length.
The current HDF4.2.5 reference manual still points to the 64 character maximum for the vgroup name, which needs to be corrected.
Tested at linux 32-bit