suzerain: add dox

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@43221 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #3022 new radialflow specification

Per #3020, the definition of the baseflow has
changed.  This updates the parameter processing accordingly.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@43222 0bd85f0b-c151-43b9-a1e9-27231104551f