suzerain: #3088 T_w \approx T_{iw} cutoff

See updates the model document within this ticket
for what changed.  See the Redmine ticket update 5 for why.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44504 0bd85f0b-c151-43b9-a1e9-27231104551f