Commercial slot loader

/cc @kenlim @kelvin-chappell @phamann

Ready to merge. Can I get a hallelujah?

Included is a simple commercial component loader, packaged and managed as part of our application but designed to provide an sensible interface for OAS/DFP to load our own adverts (based on AMD).

It :-

- Exists
- Provides an interface to load each component
- Passes section and keyword to a travel component from the commercial server
- Passes segment information to the commercial component
- Injects an oastoken in to the component response

The ad server would have to execute this for each slot it wanted to display a component in:-

https://gist.github.com/commuterjoy/7986819

A convenience method can be called to load each component,

```
var travel = new CommercialComponent(opts).travel(slot),
    masterclasses = new CommercialComponent(opts).masterclasses(slot),
    jobs = new CommercialComponent(opts).jobs(slot),
    soulmates = new CommercialComponent(opts).soulmates(slot);
```

![tumblr_mwqfv2iv7p1sm2o07o1_1280](https://f.cloud.github.com/assets/84996/1723743/74770486-6260-11e3-8914-63758452e6be.png)