[e] (0) Rejigger how scripts are described. Work in progress.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=22863
Affected topics: HTML, Workers

git-svn-id: http://svn.whatwg.org/webapps@8124 340c8d12-0b0e-0410-8428-c7bf67bfef74