ES6 export function requires trailing semicolon.

@stefanpenner brought this to my attention. Per @wycats and @domenic the trailing semi-colon is required for the following scenarios:

```javascript
export default function () { return 'foo'; };
export function foo () { return 'bar'; };
```

For reference:

https://people.mozilla.org/~jorendorff/es6-draft.html#sec-exports