Commercial Components - Alpha

This is a first rough attempt at responsive commercial components - Travel, Masterclasses, Jobs and Soulmates. Designs still pending.

Also includes an A/B test to display the travel component to repeat visitors of the Travel section in place of the MPU.

![ad-small](https://f.cloud.github.com/assets/518943/1542698/642369c4-4d4a-11e3-9e1a-ef895cd5585f.png)
![ad-medium](https://f.cloud.github.com/assets/518943/1542700/65c20100-4d4a-11e3-9798-bd995da0f4a1.png)
![ad-wide](https://f.cloud.github.com/assets/518943/1542701/675b1e16-4d4a-11e3-8170-07bced631e9b.png)


![commercial-mpu](https://f.cloud.github.com/assets/518943/1542726/ac9662ba-4d4a-11e3-9124-bc0935dca456.png)