Twenty Fourteen: add brief inline help text for Featured Content controls in Customizer. See #25837.

git-svn-id: http://develop.svn.wordpress.org/trunk@26045 602fd350-edb4-49c9-b593-d223f7449a82
Add some missing braces to get_bookmarks() which was causing an early return. Introduced in [25934]. See #25468. Fixes #25874


git-svn-id: http://develop.svn.wordpress.org/trunk@26046 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fourteen: performance win by reducing the number of post thumbnail sizes needed in the theme. Props iamtakashi, closes #25876.

git-svn-id: http://develop.svn.wordpress.org/trunk@26047 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fourteen: fix case of featured posts `has_tag()` check that was adding an empty `footer` element. See #25868, props iamtakashi.

git-svn-id: http://develop.svn.wordpress.org/trunk@26048 602fd350-edb4-49c9-b593-d223f7449a82