Build skeletal inline book commercial component
Enable book ad to load through js
Cache not-found results with no cache
Cater for no factboxes
Make some book properties optional
Add click-through tracking codes
Merge branch 'master' into kc-book-inline

Conflicts:
	common/app/assets/javascripts/modules/commercial/loader.js
Fix formatting
Merge pull request #3127 from guardian/kc-book-inline

Create new endpoint for inline book ad