Copy media modal colors out of colors.css and into media-views.css, as the modal can be triggered on the front end.

Merges part of [26929] to the 3.8 branch.

props avryl.
props collinsinternet for the initial patch.
fixes #26677.

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git-svn-id: http://core.svn.wordpress.org/branches/3.8@26869 1a063a9b-81f0-0310-95a4-ce76da25c4cd