started testing. added density matrix outputting Stuff that works: F =
IIF = IIIIF, PQF = IPIQF, F(RI) = RRF.  Stuff that doesn't work:
symmetry in full transformation.  Stuff that probably works (?):
PPF = P*P*F using python for contractions (getting maximum difference
elements of about 1e-7 - 1e-9; tried cranking up precision to double
precision, but it didn't help)