Updated Sanitizer for HTML5

Sanitizer should recognize HTML elements
and attributes.

New Allowed Elements:

  article aside audio canvas command details
  dialog figcaption figure footer header
  hgroup mark meter nav progress rp rt ruby
  section source summary time video war 
       
(OK, audio and video were already there)

New Allowed Attributes:

  autocomplete contenteditable contextmenu
  draggable formaction icon low max min
  open optimum pattern placeholder preload
  pubdate required reversed  spellcheck step
  wrap

Attributes removed:

  abbr charset loopcount loopend loopstart
  noshade nowrap rev rules 


Maruku supports @start and @reversed on
ordered lists. It doesn't seem to support
IALs on li elements, so you still can't
attach @value to an li.

vendor/plugins/maruku/lib/maruku/output/to_html.rb

@@ -410,7 +410,9 @@ It is copied as a standard HTML attribute.
 		[['pre'], attrs],
 		[['q', 'blockquote'], attrs+[:cite]],
 		[['ins','del'], attrs+[:cite,:datetime]],
-		[['ol','ul','li'], attrs],
+		[['ol'], attrs+[:reversed, :start]],
+		[['ul'], attrs],
+		[['li'], attrs+[:value]],
 		['table',attrs+[:summary, :width, :frame, :rules, :border, :cellspacing, :cellpadding]],
 		['caption',attrs],	
 		[['colgroup','col'],attrs+[:span, :width]+cellhalign+cellvalign],