Potential issues in `scico.solver`

[bwohlberg]

The comment on this line in scico.solver.minimize

https://github.com/lanl/scico/blob/4eb21c103b5ec135f7a5a05f933cb0e58b7e64af/scico/solver.py#L216

is incorrect. This should be edited, and it should be confirmed that the functions does work for BlockArray input.

It's not clear whether the use of nonlocal and the "with side effects" is really necessary

https://github.com/lanl/scico/blob/4eb21c103b5ec135f7a5a05f933cb0e58b7e64af/scico/solver.py#L233-L250

It would be worth confirming this or simplifying the code.