Twenty Fourteen: Fix gallery posts in the ephemera widget. Props iamtakashi, fixes #25740.

git-svn-id: https://develop.svn.wordpress.org/trunk@25970 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fourteen: clean up post thumbnail naming. Props iamtakashi, fixes #25718.

git-svn-id: https://develop.svn.wordpress.org/trunk@25971 602fd350-edb4-49c9-b593-d223f7449a82