Add match previews to the football match navs

Searches for squad sheets / match previews alongside checking for the
minute by minute and match report. This brings the whole match
experience into one place from before the match starts to after it is
done.
Merge remote-tracking branch 'origin/master' into previews-in-match-nav

Conflicts:
	common/app/assets/javascripts/bootstraps/football.js
Add test fixture for preview in football matchnav
Merge pull request #3664 from guardian/previews-in-match-nav

Add match previews to the football match navs