Russell Owen, I gather you made not need this as urgently as you once thought, but it's now complete as far as I'm concerned, and it's time to get it reviewed. As the main consumer, I'm afraid you're also the natural reviewer.
There's a fair amount of new code here (especially the second commit, which adds the whole afw/math/polynomials directory). For that commit, it may be helpful to start with the namespace documentation for lsst::afw::math::polynomials (in afw/math/polynomials.h) to get the big picture up front.
I've also created a number of tickets (linked to this one) to do the second half of the integration and refactoring this library represents (basically, I gathered a lot of code from a lot of places and cleaned it up and made it work together, without going back and changing the places I took it from). None of those is totally trivial, so I don't think it makes sense to do any of them here.