Allow tonal override in items

### Before

![screen shot 2014-08-14 at 12 59 27](https://cloud.githubusercontent.com/assets/85783/3919580/9d5e67a2-23aa-11e4-80cd-27557cc297d6.PNG)


### After

![screen shot 2014-08-14 at 12 59 35](https://cloud.githubusercontent.com/assets/85783/3919581/a02e9b6e-23aa-11e4-87b8-828f4ac10538.PNG)

![ ](http://media.giphy.com/media/TGc9wy9vKl0uA/giphy.gif)
you're right, the parameter name has to be explicitly specified, since you're not overriding the 3rd param.