Right now, the equation of state classes depend on the user to input the correct value of non_interacting for the particle inputs. This is not very graceful...
Only the "ms" part of the quarks is referenced, so we should rewrite to use only double's as function arguments, and avoid passing pointers to quark objects.
There are two calc_e() functions that solve. One is specially designed to work without a good initial guess. Possible the other calc_e() function should be similarly designed?
Make sure that this class properly handles particles for which inc_rest_mass is true/false
It might be nice to remove explicit reference to the meson masses in functions which only compute nuclear matter since they are unnecessary. This might, however, demand redefining some of the couplings.