Python binding to Manifold.Split() does not work about manifold

[rsaccon]

I just managed to get my local build working, tested the modified binding, @zalo Split works now as expected, thanks.

[zalo]

Ah yeah, nanobind doesn't like that it returns an std::pair...

It would have to be replaced with something like:

      .def("split", [](Manifold &self, Manifold& cutter) {
            auto p = self.Split(cutter);
            return nb::make_tuple(p.first, p.second);
           },
           nb::arg("cutter"),
           "Split cuts this manifold in two using the cutter manifold. The "
           "first result is the intersection, second is the difference. This "
           "is more efficient than doing them separately."
           "\n\n"
           ":param cutter: This is the manifold to cut by.")

Having trouble getting Manifold built on my machine or I'd test this and make a PR...

[rsaccon]

I also tried to build locally on my old intel mac, finally was able to build, but my attempt to use the local built bindings (the not yet modified ones) failed, so many things can go wrong, well, I guess I have to wait for the next pipy release for this Split() binding to work ...

[zalo]

If a version of this PR #593 works, you might be able to extract a working version of the Python wheel from the Github Actions build.