[FEZ-SDL2] Support for left/right vibration on Mac

This adds support for separate left/right controller vibration, on Mac OS X. Currently this works with the patched 360Controller driver available at https://github.com/d235j/360Controller/releases .

This should not affect other controllers or drivers, but may affect force feedback joysticks which have exactly two force feedback axes (though would anyone really play Fez with one of those?)