Updates homepage promoted content.

* 'The cost of buying a used car' replaces 'Borrowing - get the facts'.
Reposition Car campaign images
Run Karma in isolation

The rake task can’t run alongside other environments.
Update MAS Development Dependencies
Karma doesn’t work with a RAILS_ENV of test >_<
Merge pull request #495 from moneyadviceservice/f/homepage_10072014

Updates homepage promoted content.
Small note about feature toggles and testing locally.
Merge pull request #497 from moneyadviceservice/doc/feature-toggles

Small note about feature toggles and testing locally.
Fix Welsh months names
Update style guide to support news
Add news index feature
Add news index action
Update news article reader repository
Add index action to NewsController
Add all method to news repository
Add news reader
Add intro to NewsArticleDecorator
Add news index view
Add pagination to the public website request
News reader returns a collection of NewsArticle