suzerain: NRBC a, b, and c handling looking good

Updates the .def with what I've learned from the 0-0 case.
Clean up work on several TODOs but, hallelujah, the consistency
tests with the forward operator are passing.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44038 0bd85f0b-c151-43b9-a1e9-27231104551f