ots and diffuse rates are fundamentally different since ots must be
constantly updated as the solution progresses, but diffuse needed only
once per zone
so they are done in two different sets of routines

ots rates for all elements, done in RT_OTS.c

diffuse, outward continua for all species done in  RT_diffuse

add otslines

hydrogen lines

level1 lines

atom_level2 lines

forbidden lines

===================================================

RTMakeStat and RTMakeWind call escape prob routines, set pumping, etc.

escape probabilities are in rtescprob.

===================================================

optical depths originally estimated in RT_tau_init
optical depths are incremented in RT_Tau_inc
at end of iteration optical depth scale is reset in RT_tau_reset (in rtoptdepthinit.c)

