Added showExpired to the content api.

You can now query for expired content (if you have permissions) and the content will know whether it is expired or not.
Cleaned up some white space
All endpoints will now correctly parse isExpired
Not everything needs fixExpired
Merge branch 'master' of github.com:guardian/open-platform-content-api-scala-client into expired-content

Conflicts:
	build.sbt
	readme.markdown
Merge pull request #10 from guardian/expired-content

Expired content