[giow] (3) Move more towards the browsers for <option> selectedness vs dirtiness. This doesn't quite match any browser exactly, so all browsers would have to change to match it. If there's a reason (e.g. backcompat) to prefer a different model, please reopen the bug and let me know.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=23574
Affected topics: DOM APIs, HTML

git-svn-id: http://svn.whatwg.org/webapps@8297 340c8d12-0b0e-0410-8428-c7bf67bfef74