Add half-width standard item slices, including Small Slow V

![screen shot 2014-09-22 at 16 31 30](https://cloud.githubusercontent.com/assets/867233/4358846/8f9838be-426d-11e4-985e-9c93c1ca9807.png)

Interesting that you went for two `SingleItem` to create the row pattern rather than a `Rows` class.