Twenty Fifteen: correct list indentation in older IE versions.

Props iamtakashi, fixes #30074.



git-svn-id: https://develop.svn.wordpress.org/trunk@30012 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: valid HTML for accessible child page menu expanding and collapsing -- now with even better accessiblity.

Props afercia, davidakennedy, iamtakashi, fixes #30083.



git-svn-id: https://develop.svn.wordpress.org/trunk@30013 602fd350-edb4-49c9-b593-d223f7449a82
Add the ability for a customizer control to render its controls via a JavaScript template. Switches the default color picker control to a JavaScript template. See #29572. Props celloexpressions

git-svn-id: https://develop.svn.wordpress.org/trunk@30014 602fd350-edb4-49c9-b593-d223f7449a82