[giow] (3) Update document.title to work like textContent (also defines how things work with mutation observers)
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=24224
Affected topics: DOM APIs

git-svn-id: http://svn.whatwg.org/webapps@8404 340c8d12-0b0e-0410-8428-c7bf67bfef74