Add a new admin color scheme picker, overriding `admin_color_scheme_picker` with new HTML. 
Show the selected color scheme, with a dropdown to look & select from the rest. 
If no-js, show the full list of color schemes.



git-svn-id: https://plugins.svn.wordpress.org/mp6/trunk@764572 b8457f37-d9ea-0310-8a92-e5e31aec5664