Many-to-many mapping between settings and controls.
* Settings and controls have been separated in both the PHP (WP_Customize_Setting, WP_Customize_Control) and the JS (wp.customize.Setting, wp.customize.Control).
* While most settings are tied to a single control, some require multiple controls. The 'header_textcolor' control is a good example: to hide the header text, header_textcolor is set to 'blank'.
Add 'Display Header Text' control.
A handful of miscellaneous bugfixes along the way.
Notes:
* Controls should be separated out a bit more; juggling type-specific arguments in the switch statement is rather inelegant.
* Page dropdowns are currently inactive and need to be re-linked.
git-svn-id: https://develop.svn.wordpress.org/trunk@20295 602fd350-edb4-49c9-b593-d223f7449a82
* prepare_controls() now removes any settings and sections that return false for check_capabilities().
* Added maybe_render() methods to both settings and sections that call the protected render() methods.
* Stop firing front-end preview functionality when rendering the controls.
* Merged the WP_Customize_Setting->_render_type() method into WP_Customize_Setting->render().
* Removed the 'customize_render_control-' hook; use 'customize_render_setting' instead.
* Added a property to sections and settings so they no longer rely on the global. Hooray for dependency injection.
* Shifted calls to WP_Customize_Setting->enqueue() to the 'customize_controls_enqueue_scripts' action.
* Added a theme_supports check for the header_textcolor setting.
git-svn-id: https://develop.svn.wordpress.org/trunk@20248 602fd350-edb4-49c9-b593-d223f7449a82
