Build fails on MacOS 10.13.4 / node 10.3.0

[heipei]

Hey Bondy,

same issue as with bloom-filter-cpp, care to fix? I don't have the C++ skills, otherwise I'd create a PR myself.

Related issue from bloom-filter-cpp is here: bbondy/bloom-filter-cpp#4

Issue:

../hash_set_wrap.cc:61:37: error: no matching member function for call to 'NewInstance'
    args.GetReturnValue().Set(cons->NewInstance(argc, argv));
                              ~~~~~~^~~~~~~~~~~