Ungron doesn't respect --no-sort option

When using the `--ungron` option I'd expect the `--no-sort` option to take effect too,
but unfortunately it's being ignored.

Example:
```sh
$ echo '{"z": "first", "a": "last"}' | gron --no-sort | gron --no-sort --ungron
{
  "a": "last",
  "z": "first"
}
```

Maybe related to #102 ?