Simplify bool ops closures, improve tests
Series bool ops are not going to be possible to dispatch to their Index counterparts, so this one I'm _mostly_ going to leave alone.  This breaks up the tests, adds an xfail for op(Series, Categorical), and fixes+tests op(series, Index).  It makes some headway in simplifying the closure so the possible paths through the code are more obvious.

There is a TODO comment on line 1113 where I think there is a potential bug, but need someone who understands the _intended_ behavior better to weigh in.