function<Type*(void)> will attempt to copy Type on return

Firstly, thank you for this wonderful library. As I was using it I found some unexpected/undesired behaviour. Wrapped function objects from std::functional will copy the result even when the result is of type pointer.
Here is my sample code to reproduce the issue.

#include <functional>
#include <pybind11/pybind11.h>
#include <pybind11/functional.h>

namespace py = pybind11;

struct Test {
    Test() {};
    Test(const Test &obj) = delete;
    int i;
};
Test* fullFunction()
{
    return new Test();
}
std::function<Test*(void)> func = &fullFunction;

PYBIND11_MODULE(example, m) {
    // optional module docstring
    m.attr("full") = py::cpp_function(func);
    m.attr("func") = func;
    py::class_<Test>(m,"Test")
        .def_readwrite("i",&Test::i);
}

import example
example.full()
example.func()

example.func() will result in an error: return_value_policy = copy, but the object is non-copyable!

It's my understanding that both full & func should return a Test* and that the underlying Test will not be copied however when the pybind11/functional wrapper handles it, it will attempt to copy Test*. I believe this occurs because a function object is an object and not a pointer which causes copy to be the default behaviour that is detected. Sorry if I have misunderstood anything.

Start in pybind11/functional.h and reproduce the behavior with the C++ and Python examples in the issue, comparing py::cpp_function(func) with the directly exposed function object. Trace how the wrapper selects the return policy for a Test* result; done means example.func() returns the pointer without attempting to copy the non-copyable Test.