suzerain: correct simple bugs

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42936 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: repair insertion code

It was not merely an insertion (which I think was broken)
but a unique insertion that I wanted.  That search process
looks a bit different.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@42937 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #3010 tests for thicknesses_baseflow

The easy, sane test is to require that it reproduces the
versions sans baseflow when a uniform baseflow is specified.

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