h4h5tools

This changelist puts HDF-EOS2 dimension on the parent of 'Data Fields' group, which corresponds to HDF-EOS2 Swath or Grid dataset. This changelist aims to fix name confliction occurring when an HDF-EOS2 field and an HDF-EOS2 dimension share the same name. This makes one problematic NSIDC file converted correctly, but this also has a problem. It will be handled by the next changelist.

Add test cases, too.