further clean up

Author: mrodrig6

src/forward_solver/m_imr_fd.m

@@ -528,6 +528,7 @@
     % solves temperature boundary conditions at the bubble wall
     function Tauw = Boundary_mass(prelim)
 
+        % no thermal transport in the surroundings
         Tm_trans = ones(2,1);
         T_trans = zeros(2,1);