suzerain: #2503 from radial_nozzle towards map

Have decided that, because of command line requirements, that
the radial nozzle is going to be implemented via a baseflow_map
instance that knows nothing about the baseflow is implemented.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42573 0bd85f0b-c151-43b9-a1e9-27231104551f