Add acentric factor for Air; closes #1001
Add acentric factor for Air; closes #1001

JonWel/CoolProp,DANA-Laboratory/CoolProp,dcprojects/CoolProp,DANA-Laboratory/CoolProp,henningjp/CoolProp,henningjp/CoolProp,DANA-Laboratory/CoolProp,dcprojects/CoolProp,CoolProp/CoolProp,henningjp/CoolProp,henningjp/CoolProp,JonWel/CoolProp,dcprojects/CoolProp,CoolProp/CoolProp,henningjp/CoolProp,henningjp/CoolProp,CoolProp/CoolProp,JonWel/CoolProp,CoolProp/CoolProp,JonWel/CoolProp,CoolProp/CoolProp,dcprojects/CoolProp,JonWel/CoolProp,CoolProp/CoolProp,henningjp/CoolProp,DANA-Laboratory/CoolProp,CoolProp/CoolProp,DANA-Laboratory/CoolProp,DANA-Laboratory/CoolProp,dcprojects/CoolProp,CoolProp/CoolProp,dcprojects/CoolProp,JonWel/CoolProp,DANA-Laboratory/CoolProp,dcprojects/CoolProp,JonWel/CoolProp,henningjp/CoolProp