[giow] (3) Bring the 'microtask checkpoint' invocation at the end of scripts more into line with implementations, and unrelated editorial fixes.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=22185
Affected topics: HTML

git-svn-id: http://svn.whatwg.org/webapps@7950 340c8d12-0b0e-0410-8428-c7bf67bfef74

Author:    ianh <ianh@340c8d12-0b0e-0410-8428-c7bf67bfef74>