Read the variables associated to the Abinit header.

        Return :class:`AbinitHeader`

def read_abinit_hdr(self):
        """
        Read the variables associated to the Abinit header.

        Return :class:`AbinitHeader`
        """
        d = {}
        for hvar in _HDR_VARIABLES.values():
            ncname = hvar.etsf_name if hvar.etsf_name is not None else hvar.name
            if ncname in self.rootgrp.variables:
                d[hvar.name] = self.read_value(ncname)
            elif ncname in self.rootgrp.dimensions:
                d[hvar.name] = self.read_dimvalue(ncname)
            else:
                raise ValueError("Cannot find `%s` in `%s`" % (ncname, self.path))
            # Convert scalars to (well) scalars.
            if hasattr(d[hvar.name], "shape") and not d[hvar.name].shape:
                d[hvar.name] = np.asscalar(d[hvar.name])
            if hvar.name in ("title", "md5_pseudos", "codvsn"):
                # Convert array of numpy bytes to list of strings
                if hvar.name == "codvsn":
                    d[hvar.name] = "".join(bs.decode("utf-8").strip() for bs in d[hvar.name])
                else:
                    d[hvar.name] = ["".join(bs.decode("utf-8") for bs in astr).strip()
                            for astr in d[hvar.name]]

        return AbinitHeader(d)