Optimise App Layout for Tablet

![screen shot 2017-06-04 at 15 28 28](https://cloud.githubusercontent.com/assets/1044653/26762454/a4532026-493a-11e7-8584-f90550a5a04b.png)
![screen shot 2017-06-04 at 15 28 17](https://cloud.githubusercontent.com/assets/1044653/26762453/a450af44-493a-11e7-9788-9af3d2f8b10c.png)

Common header needs to be updated for larger devices