[e] (0) Use more WebIDL (and some minor editorial fixes I forgot to commit before making the WebIDL change)
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=20286
Affected topics: Canvas, DOM APIs, HTML, HTML Syntax and Parsing

git-svn-id: http://svn.whatwg.org/webapps@7822 340c8d12-0b0e-0410-8428-c7bf67bfef74
[giow] (3) Make :invalid match <fieldset>s that contain invalid controls.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=20585
Affected topics: HTML

git-svn-id: http://svn.whatwg.org/webapps@7823 340c8d12-0b0e-0410-8428-c7bf67bfef74