Validate pingback source URIs. Less verbose errors.



git-svn-id: http://core.svn.wordpress.org/trunk@23329 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.6-alpha-23334. TinyMCE updated.

git-svn-id: http://core.svn.wordpress.org/trunk@23334 1a063a9b-81f0-0310-95a4-ce76da25c4cd