Add `calc_rhomolar_critical` closes #748
Add `calc_rhomolar_critical` closes #748
DANA-Laboratory/CoolProp,CoolProp/CoolProp,dcprojects/CoolProp,dcprojects/CoolProp,henningjp/CoolProp,dcprojects/CoolProp,dcprojects/CoolProp,henningjp/CoolProp,DANA-Laboratory/CoolProp,DANA-Laboratory/CoolProp,DANA-Laboratory/CoolProp,CoolProp/CoolProp,DANA-Laboratory/CoolProp,DANA-Laboratory/CoolProp,DANA-Laboratory/CoolProp,CoolProp/CoolProp,JonWel/CoolProp,CoolProp/CoolProp,CoolProp/CoolProp,dcprojects/CoolProp,JonWel/CoolProp,CoolProp/CoolProp,JonWel/CoolProp,dcprojects/CoolProp,JonWel/CoolProp,henningjp/CoolProp,henningjp/CoolProp,JonWel/CoolProp,henningjp/CoolProp,CoolProp/CoolProp,JonWel/CoolProp,henningjp/CoolProp,dcprojects/CoolProp,CoolProp/CoolProp,henningjp/CoolProp,henningjp/CoolProp,JonWel/CoolProp