Changing default in `a2o(all=False)` to `a2o(all=True)`

[zerothi]

Describe the issue Generally, a2o is used so many places, and generally its use involves getting all orbitals of an atom. Therefore I would suggest that we should change the default to all=True.

I think this could improve things as one can then pass the a2o method around in more stringent ways.