fterEach` phase of the
current Mocha `Suite`.

## Data-bound templates

Data-binding systems are also supported, as long as your (custom) template
elements define a `stamp(model)` method that returns a document fragment. This
allows you to stamp out templates w/ custom models for your fixtures.

For example, using Polymer 0.8's `dom-template`:

```html
<test-fixture id="bound">
  <template is="dom-template">
    <span>{{greeting}}</span>
  </template>
</test-fixture>
```

You can pass an optional context ar