expose AnswerAreaRenderer on Perseus
expose AnswerAreaRenderer on Perseus

Summary:
We might or might not want this for worked examples;
I'm exposing it so it's easy to try if we feel like trying.

Auditors: alex, eliana

ariabuckles/perseus,sachgits/perseus,abe4mvp/perseus,iamchenxin/perseus,chirilo/perseus,junyiacademy/perseus,ariabuckles/perseus,chirilo/perseus,learningequality/perseus,abe4mvp/perseus,sachgits/perseus,daukantas/perseus,learningequality/perseus,alexristich/perseus,iamchenxin/perseus,ariabuckles/perseus,ariabuckles/perseus,huangins/perseus,daukantas/perseus,alexristich/perseus,huangins/perseus,junyiacademy/perseus