Unique slot ID for mobile and styling of DFP ads

Slot IDs need to be unique

Also, use the same styling as for OAS

### Top banner

![screen shot 2014-03-31 at 13 18 33](https://cloud.githubusercontent.com/assets/74132/2566962/d6422960-b8ce-11e3-82e6-c064af343168.jpeg)

### Inline

![screen shot 2014-03-31 at 13 18 43](https://cloud.githubusercontent.com/assets/74132/2566963/d643f204-b8ce-11e3-91a1-cf529c5679d0.jpeg)