HeatMap-type answers need to be added to the API

I was surprised that heatmap-type questions (with defined regions on an image) don't expose a user's selection in the API. Seems like this is just some sort of oversight since it is clearly available in the online results display and in the email-delivered results. Just make it work like the other question types, and maybe add the coordinates (but I don't need that at all, just want to know which regions were selected).

We are having to re-build all of our image heatmap questions back into multiple-choice ones that reference a labelled image. This is worse for our user experience and wasted our time since there was indication that this question type doesn't work with the API.