Needed to adjust tolerance for my Mac.
Rename get_reaction_ptr to build_reaction.
Also a leaner implementation.
Return a reference to Reaction instead of a pointer.
Reaction is now a reference.
Should be all white space/brackets/indentation/untabify.
Reaction is a reference now.
print_chemical_scheme now takes an std::ostream.
That loop should be over n_species().
Actually call print_chemical_scheme at least 1 time.