* Rename WP_Customize to WP_Customize_Manager.
* Move customize-controls.php to wp-admin/customize.php.
* Make customize.php the formal entry point, rather than admin.php?customize=on.
* Rename is_current_theme_active() to is_theme_active().
* Add getters for the theme, settings, controls, and sections properties.
* Allow customize.php (no ?theme=) to load the active theme. Not used yet.
see #20736.
git-svn-id: https://develop.svn.wordpress.org/trunk@20852 602fd350-edb4-49c9-b593-d223f7449a82
