add buy_item, sell_item method; revise gold.setter range check; add health_regen, magic_resist, armor, atk_speed, ad_dmg, ap_dmg property setter
add buy_item, sell_item method; revise gold.setter range check; add health_regen, magic_resist, armor, atk_speed, ad_dmg, ap_dmg property setter

ivoryhuang/LOL_simple_text_version