Improve Atom feed titles

In many atom feed consumers the title gets trucated. It is important
that the actuall title of contents is first. This moves them first an
also unifies the style of them.

https://www.pivotaltracker.com/story/show/45026361
Merge pull request #538 from alphagov/feed-title-updates

Improve Atom feed titles

https://www.pivotaltracker.com/story/show/45026361