* Allow passing settings in keyed object (e.g. `settings: { default: 'id' } ), or as an array (e.g. `settings: [ 'id' ]`) with first being default; again, `Setting`/`Value` objects may be supplied instead of IDs.
* Allow a single setting to be supplied with just a single `setting` param, either a string or a `Setting`/`Value` object.
* Update `changeset_status` and `scheduled_changeset_date` to be added dynamically with JS and simply passing of `api.state()` instances as `setting`.
* Introduce a `data-customize-setting-key-link` attribute which, unlike `data-customize-setting-link`, allows passing the setting key (e.g. `default`) as opposed to the setting ID.
* Allow `WP_Customize_Control::get_link()` to return `data-customize-setting-key-link` when setting is not registered.
* Eliminate `default_value` from `WP_Customize_Date_Time_Control` since now comes from supplied `Value`.
* Export status choices as `wp.customize.settings.changeset.statusChoices`.
* Export date and time formats as `wp.customize.settings.dateFormat` and `wp.customize.settings.timeFormat` respectively.
Props westonruter, sayedwp.
See #39896, #30738, #30741, #42083.
Fixes#37964, #36167.
git-svn-id: https://develop.svn.wordpress.org/trunk@41750 602fd350-edb4-49c9-b593-d223f7449a82
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