Add a contrasting border to admin feature pointers.

Merges [26970] to the 3.8 branch.

props iammattthomas.
fixes #26689.

Built from https://develop.svn.wordpress.org/branches/3.8@26971


git-svn-id: http://core.svn.wordpress.org/branches/3.8@26850 1a063a9b-81f0-0310-95a4-ce76da25c4cd