print line optical depths needs to be cleaned up
the accrued mess of the past few decades around the implementation of the print line optical depths command needs to be cleaned up. hii_paris is an example.
prt_alltau is called to print optical depths. most of this routine consists of hacks to get optical depths for the very old ways to doing the lines to print.
around line 152 it calls prtmet which then prints all line optical depths in the new structures. this should be the only print. need to clean out most of prt_aoltau and merge prtmet into it
currently prt_alltau prints continuum optical depths at all edges of H and He iso sequences. is this needed? same info is available in punch optical depths. this print made sense when there were only a very few levels for the sequences - now just oo much info?
prt_alltau also give old and new optical depths. this is good for examining concergence, which is done by code internally. is this print needed? if so should it be just a few of the lower lines of the H and He sequences?
prt_alltau does a correction for spherical geometry to only print one sided tau but prtmet does not do this. which do we want?