hdf5_ep

New API functions
Description:
    Added functions to query chunk information:

        H5Dget_num_chunks(dset_id, fspace_id, *nchunks)
            Gets the number of written chunks that intersect with the given
            dataspace.  However, in this version, the intersection is not
            yet completed.  Thus, the number of all written chunks will be
            returned.

        H5Dget_chunk_info_by_coord(dset_id, *coord, *filter_mask, *addr, *size)
            Given a chunk's coordinates, returns the chunk's filter, address,
            and size.

        H5Dget_chunk_info(dset_id, fspace_id, index, *coord, *filter_mask, *addr, *size)
            Given a chunk's index, returns the chunk's coordinates, filter,
            address, and size.  The chunk belongs to a set of chunks that have
            nonempty intersection with the specified dataspace.  However, in
            this version, the intersection is not yet completed, and the index
            is of all the written chunks.

Platforms tested:
    Linux/64 (jelly)
    Linux/64 (platypus)
    Darwin (osx1011test)