Twenty Thirteen: better contrast for footer text and form "allowed tags" text, props sabreuse. See #23513.

git-svn-id: http://core.svn.wordpress.org/trunk@23613 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Thirteen: better contrast for page links, props sabreuse. See #23513.

git-svn-id: http://core.svn.wordpress.org/trunk@23614 1a063a9b-81f0-0310-95a4-ce76da25c4cd