Using specific data attributes for Sketch
This is an amazing tool. Haven't run it yet, but I have been wanting to build this myself. What would be amazing is to have control over some Sketch specific properties by passing those props through data attributes.

As an example imagine the following component:

```html
<div data-sketch-ignore>
  <div data-sketch-symbol="SearchInput">
    <input class="SearchInput" data-sketch-resize="stretch" data-sketch-layer-name="name" />
  </div>
</div>
```

I can think of some props like:

* data-sketch-layer-style
* data-sketch-link-object

Haven't thought it through all the way, but I could see it be helpful to have some control of the Sketch output.
