add number of corr functions for sorting orbits, update max_lp and fix hierarchy tests

[lbluque]

• fixed hierarchy tests from fix Fix generation of orbits #255
• updated max_lp in cluster search to max distance to site.
• add number of corr functions for sorting orbits. This will changes the order of correlation functions!

Checklist

• Code is in the standard Python style.
  Run pycodestyle and flake8
  on your local machine.
• Docstrings have been added in the Google docstring format.
  Run pydocstyle on your code.
• Tests have been added for any new functionality or bug fixes.
• All existing tests pass.

[qchempku2017]

Why is it necessary to change the ordering of orbits? Will this change make the old smol cluster subspace file and coefficients file invalid? If so, how can we rescue our old saves?