Current implementation of hxFromBytes incompatible with Node 4.x

Before `hxFromBytes(foo)` would generate

```js
new Buffer(foo.b.bufferValue)
```

but that changed with HaxeFoundation/hxnodejs@19a1e2b9af60860b0f0b9e0d5f2a933ff12c6031 (and HaxeFoundation/hxnodejs@9b24a891e640beca1bb57dea31800acafe696ebb) to

```js
new Buffer(foo.b.bytes, foo.b.byteOffset, foo.b.byteLength)
```

However, the history of the `new Buffer(arrayBuffer, offset, length)` NodeJS constructor [isn't as linear as one would hope](https://nodejs.org/dist/latest-v8.x/docs/api/buffer.html#buffer_new_buffer_arraybuffer_byteoffset_length):


Since the constructor isn't supported in Node 4.x, the current implementation has the effect of calling `new Buffer(foo.b.bytes)`, making the new buffer point to the _entire_ underlying array buffer of `foo`, that _will also contain data for other buffers_, because of pooling.