[misc] add ndpointer that can handle None/null
[misc] add ndpointer that can handle None/null

gkc1000/pyscf,gkc1000/pyscf,gkc1000/pyscf,sunqm/pyscf,gkc1000/pyscf,sunqm/pyscf,sunqm/pyscf,sunqm/pyscf,gkc1000/pyscf