Method operator new

tests/test_factory_constructors.cpp:371–374

        ~NoisyAlloc() { py::print("~NoisyAlloc()"); }

        static void *operator new(size_t s) {
            py::print("noisy new");
            return ::operator new(s);
        }
        static void *operator new(size_t, void *p) {
            py::print("noisy placement new");
            return p;