This is in the parser where various attributes of the underlying XML node are used to determine the question type, or added to the question instance.

However, at the end, a dict of the raw attributes gets stored, in case there are any unrecognized ones.  Before, when the form was written, there were special cases for a couple of these attributes (appearance and jr:count) not to write them out if they were in the dict of the raw attributes, because they might have changed.  But there were other attributes in there, and the control element only has a couple, but I wanted to do the raw attribute thing for bindElement, so I needed to make this popAttr thing, so we wouldn't have to do stuff manually.

This is just one section of the parser, and I replaced all the instances of `attr()` with `popAttr()`, and there are no two calls on the same attrs.

Bleh, words.