Ampersand does not parse correctly

Summary: The heart of the recipe is: put an ampersand in a Chart Label for a Rating. Display the Summary for that Rating inside of the Instance Edit View of the Review Model that incorporates it.

What's going on is that, if we escape ampersand naively in the QText parser (as it had been doing), then it fouls up the parsing of entities like apos and quot. But if we don't, and we let it simply pass through, then attempting to parse the resulting markup in XmlHelpers crashes because it is malformed XML.

I suspect that we have to special-case ampersand in the QText parser, detect whether it is being used in an entity, and escape it only if not.