Allow the content of no-title audio, video, quote, and image posts to be blanked.

props wonderboymusic. fixes #23623.

git-svn-id: http://core.svn.wordpress.org/trunk@23986 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-beta1-23987.

git-svn-id: http://core.svn.wordpress.org/trunk@23987 1a063a9b-81f0-0310-95a4-ce76da25c4cd