fix: populate _order_refs when processing AddOrderMessage#71

vgreg merged 2 commits intomainvgreg/MeatPy:mainfrom

68-parts-of-code-not-initialized-and-not-executed-because-self_order_refs-is-not-updatedvgreg/MeatPy:68-parts-of-code-not-initialized-and-not-executed-because-self_order_refs-is-not-updatedCopy head branch name to clipboard