Fix linking problems on Windows

[federico-terzi]

I've fixed linking problems on Windows and most examples work correctly.
That said, the ones that use async functions fail. For example, the "class" example fails with:

obj.plusTwo(10).then( (val) => {
    ^

TypeError: napi call failed InvalidArg
    at Object.<anonymous> (C:\Users\Freddy\Documents\WiseTime\node-bindgen\examples\class\test.js:49:5)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:743:3)

[sehz]

Thanks for work. Linking flag looks ok, only issue I see is downloading binary

[federico-terzi]

You're welcome!

[sehz]

All test cases works! Thanks. merged