Add ordered axis for heat map

[htz1992213]

Summary

Include a summary of major changes in bullet points:

• Allow ordered axis for the heat map function

[rkingsbury]

Did some testing just now. I think you need some extra logic in core.get_heatmap, line 1036. Otherwise this part of the code can't handle a list input

        if isinstance(cluster_terminal, str):
            terminal_atom_type = [cluster_terminal]
        for i in cluster_terminal:
            terminal_atom_type = self.select_dict.get(i)
            assert terminal_atom_type is not None, "{} not defined in select_dict".format(i)

[htz1992213]

@rkingsbury Oh I see, thanks