* Switch to the built-in method of providing a back link in `wp_die()` for the Customizer
* Use WP_DEFAULT_THEME for both arguments during theme switching to simplify the logic
* Prevent the 3.3 and earlier theme preview action gracefully
Props obenland for patches, fixes#24441.
git-svn-id: http://core.svn.wordpress.org/trunk@24411 1a063a9b-81f0-0310-95a4-ce76da25c4cd