Focus styling: bring the blue glow to more places.

Handles color picker, theme browser, help/screen options, TinyMCE dialog buttons, jQuery UI dialog buttons, and buttons in color schemes.

props avryl, celloexpressions. fixes #28267.

Built from https://develop.svn.wordpress.org/trunk@29616


git-svn-id: http://core.svn.wordpress.org/trunk@29390 1a063a9b-81f0-0310-95a4-ce76da25c4cd