removeStyle helper

There should be a helper for removing style attributes from a set of elements

* Add fixtures (requirejs-text is required)
* Using classes to track which items to use for which tests (may not stick)

**Reviewers:** @scalvert 

#### How to test:
Update tests/runner/main.js manually:

```
            var tests = [
                '../../tests/unit/capitalizeTests.js',
                '../../tests/unit/removeStyleTests.js'
            ];
```
Is this test aimed at testing the chainability of Zepto? Ensuring that the removeStyle extension continues the chain?