Expose the API on the scope as "vg".

Sometimes it's easier/better to access the API directly from the template - without using plugins.
```html
<videogular>
  <video ...>
  <div class="controls"
    hm-tap="vg.playPause()"
    hm-double-tap="vg.toggleFullScreen()"
    ></div>
</videogular>
```