fix(rxModalAction): fix #594, modal actions to be buttons, not links

![rxmodalaction-1](https://cloud.githubusercontent.com/assets/33945/4799053/326bcec2-5e19-11e4-889b-1640c40bf104.png)
![rxmodalaction-2](https://cloud.githubusercontent.com/assets/33945/4799054/328a8d1c-5e19-11e4-9bc1-91ca748e069f.png)

Do you know if this is doing anything? We set it on the directive scope, but we don't appear to use it on the template