Significant questions brought up by Berker Peksağ in his review of the latest patch (thanks for the review!):

1. Should the tolerance parameters be keyword-only? Berker suggests that they should be. I agree.

2. Should the math.isclose() tests be split into a separate TestCase class with many separate methods? It is currently a single method which does all of the testing for math.isclose(). (Chris's original code has it separated into several TestCase classes; I consolidated it into a single method to keep in line with the current structure of the math module's tests.)