Update mac binary

@andrew as per #20 you said:

> So I built a new mac binary from scratch and git says that it's no different to the current one, all the tests are passing but it would be good to get a sanity check from @keithamus can check that he gets the same result.

I ran the update steps on node-sass and built a fresh binary, which git says looks different the one in `master` here. The tests pass on my machine.