Design refinements - Event detail

A couple of minor design refinements from Ben W to the event detail pages.

**1. Event type should link to the listings page**

![event-detail-link mov](https://cloud.githubusercontent.com/assets/123386/5570460/9af8b806-8f79-11e4-88e1-71fdb2b76786.gif)

![masterclass-detail-link mov](https://cloud.githubusercontent.com/assets/123386/5570464/a66b26f6-8f79-11e4-9ea5-9239118d8bc1.gif)

**2. Even out spacing around details strip (was changing too much across breakpoints**

Before:
![screen shot 2014-12-29 at 16 37 12](https://cloud.githubusercontent.com/assets/123386/5570467/ad4e0164-8f79-11e4-9bd5-54e59970c209.png)

After:
![screen shot 2014-12-29 at 16 37 20](https://cloud.githubusercontent.com/assets/123386/5570470/aff8d72c-8f79-11e4-9cc5-ba6ee3a3b6c0.png)