Twenty Eleven: minor style fixes (overflow) for international blogs and...

Twenty Eleven: minor style fixes (overflow) for international blogs and replacing em dash with the proper CSS value for the entity. Props matveb, see #17198

git-svn-id: https://core.svn.wordpress.org/trunk@17719 1a063a9b-81f0-0310-95a4-ce76da25c4cd