TODO.txt

* Move MOSpaces into Hamiltonian object (not needed at ugacc level or in other objects)

* Transform perturbation integrals using built-in functions? transform()? <--
I don't think so, because I'm not using the Matrix class to keep up with
symmetry.

* Have objects HBAR, CCPert, and CCDensity derive from CCWfn?  That would be
cleaner in that all depend on the CCWfn.  No, not sure this really is useful,
as you'd still need to pass a CCWfn as an argument.  Then again, the
declarations of the member data would already in place, e.g. no_, nv_, D1_,
D2_, t1_, t2_, etc., but I'd still need to copy the data or pointers.  Copying
the data seems like a bad idea (memory), and copying the pointers seems
dangerous.

Of course, now that I think about it, I'm *already* just copying pointers, so
the encapsulation is already broken.  For example, in the constructor for
CCLambda, I pass a shared_ptr to a CC wfn, which I then assign to the CCLambda
object's CC_ shared_ptr member.  I then use it as a container for various
pointers, which I use liberally through the CCLambda member functions, e.g.

  double ****t2 = CC_->t2_;
  H_ = CC_->H_;

If the CC object were to go out of scope while the CCLambda object remained in
scope, then those pieces of CCLambda would no longer be accessible, and the
object would be broken.  Bad design.