PPC/Display network traffic Splash Page

Front end implementation of Angus' PPC/display network splash page.

![ppc-screenshot](https://cloud.githubusercontent.com/assets/883598/3108364/c5c7f8c8-e68f-11e3-8d36-86e24f740f33.png)

Subject to change:
- Copy
- Page title
- Paths (/direct-debit-benefits is temporary location of this page)