List and add all the torch backed ndarray functions to current module.

def _init_torch_module():
    """List and add all the torch backed ndarray functions to current module."""
    plist = ctypes.POINTER(FunctionHandle)()
    size = ctypes.c_uint()
    check_call(_LIB.MXListFunctions(ctypes.byref(size),
                                    ctypes.byref(plist)))

    module_obj = sys.modules[__name__]
    for i in range(size.value):
        hdl = FunctionHandle(plist[i])
        function = _make_torch_function(hdl)
        # if function name starts with underscore, register as static method of NDArray
        if function is not None:
            setattr(module_obj, function.__name__, function)