Twenty Fourteen: break long words in comment content (not just anchor text). Fixes #24890, props rickalee.

git-svn-id: https://develop.svn.wordpress.org/trunk@25259 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fourteen: add styling for medialement players, props celloexpressions. See #25209.

git-svn-id: https://develop.svn.wordpress.org/trunk@25260 602fd350-edb4-49c9-b593-d223f7449a82