Show a playable audio/video preview on the Edit Attachment screen.

props wonderboymusic. fixes #23726

git-svn-id: http://core.svn.wordpress.org/trunk@23768 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Revisions: UI Update.

* Refines the UI to make it clearer and easier to use
* Introduces weighted tickmarks
* Fixes comparison bugs.

See #23497 props adamsilverstein


git-svn-id: http://core.svn.wordpress.org/trunk@23769 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23770.

git-svn-id: http://core.svn.wordpress.org/trunk@23770 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Merge remote-tracking branch 'upstream/master'