Workflow in tracers_to_PRISM

[kelslund]

To be addressed:
When converting individual tracer IDs to PRISM format using convert_ids, wrong values (wrong order) get passed to function meta_file. It is currently:
meta_file(idx, trace['mass'], mass_unit,total_mass)
Should be:
meta_file(idx, trace['mass'], mass_unit, trace['T'], trace['rho'])
At least that is the order- check that those values are actually the ones you want to use to compute initial composition, etc.