[giow] (2) Appcache manifests are all UTF-8, including resolving URLs.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=23819
Affected topics: Offline Web Applications

git-svn-id: http://svn.whatwg.org/webapps@8345 340c8d12-0b0e-0410-8428-c7bf67bfef74