Add support for arrays of Links

- Added support for arrays of Links in the _links area, as defined in HAL standard (_links => { name => [{href => ''}, {href => ''}]})

For example, see the "admin" link from the HAL standard:
```
{
  "_links": {
    "self": { "href": "/orders" },
    ...,
    "admin": [
      { "href": "/admins/2", "title": "Fred" },
      { "href": "/admins/5", "title": "Kate" }
    ]
  },
  currentlyProcessing: 14,
  shippedToday: 20,
  "_embedded": {
   ...
  }
}
```