wyuenho/backgrid — pull request #136 by aggressivex (2013-04-22 12:37:30+00:00)
Title: Fix problem that override options for footer, and others

Right now if you apply a className like below:
```javascript
var Footer = Backgrid.Footer.extend({
className: "FooterClass",
tagName: "tfoot",
});

var grid = new Backgrid.Grid({
className: 'MyTableClass',
columns: columns,
collection: collection,
footer: Footer
});
```
It will create this HTML
```html

```

This change pass only the required columns and collection options to Footer, Body and Header, so other options like className won't be overridden.