Update to latest HTML5lib

Fix that Tokenizer bug for real this time.

vendor/plugins/HTML5lib/tests/preamble.rb

@@ -68,3 +68,21 @@ module HTML5
     end
   end
 end
+
+class String
+  alias old_format %
+  define_method("%") do |data|
+    unless data.kind_of?(Hash)
+      $VERBOSE = false
+      r = old_format(data)
+      $VERBOSE = true
+      r
+    else
+      ret = self.clone
+      data.each do |k,v|
+        ret.gsub!(/\%\(#{k}\)/, v)
+      end
+      ret
+    end
+  end
+end