Update to the v0.6.0

Adds custom helpers functions to the (do) definitions

- **$addClass** classA classB
- **$removeClass** classA classB
- **$toggleClass** classB
```html
<body>
    <header data-anijs="if: click, do: $toggleClass animated flipInY">
        header (Click here)
    </header>
    <script type="text/javascript" src="anijs/src/anijs.js"></script>
    <script type="text/javascript" src="anijs/src/helpers/dom/anijs-helper-dom.js"></script>
</body>
```