Prefix the new Theme classes. Fixes #25966


git-svn-id: https://develop.svn.wordpress.org/trunk@26495 602fd350-edb4-49c9-b593-d223f7449a82
Themes: For small screen sizes, still allow access to the Customize button (Don't hide the theme actions). See #25948


git-svn-id: https://develop.svn.wordpress.org/trunk@26496 602fd350-edb4-49c9-b593-d223f7449a82