Ruby 1.9 Compatibility

Completely removed the html5lib sanitizer.
Fixed the string-handling to work in both
Ruby 1.8.x and 1.9.2. There are still,
inexplicably, two functional tests that
fail. But the rest seems to work quite well.

attic/vendor/plugins/HTML5lib/lib/html5/treewalkers/hpricot.rb

@@ -0,0 +1,48 @@
+require 'html5/treewalkers/base'
+require 'rexml/document'
+
+module HTML5
+  module TreeWalkers
+    module Hpricot
+      class TreeWalker < HTML5::TreeWalkers::NonRecursiveTreeWalker
+
+        def node_details(node)
+          case node
+          when ::Hpricot::Elem
+            if node.name.empty?
+              [:DOCUMENT_FRAGMENT]
+            else
+              [:ELEMENT, node.name,
+                node.attributes.map {|name, value| [name, value]},
+                !node.empty?]
+            end
+          when ::Hpricot::Text
+            [:TEXT, node.content]
+          when ::Hpricot::Comment
+            [:COMMENT, node.content]
+          when ::Hpricot::Doc
+            [:DOCUMENT]
+          when ::Hpricot::DocType
+            [:DOCTYPE, node.target, node.public_id, node.system_id]
+          when ::Hpricot::XMLDecl
+            [nil]
+          else
+            [:UNKNOWN, node.class.inspect]
+          end
+        end
+
+        def first_child(node)
+          node.children.first
+        end
+
+        def next_sibling(node)
+          node.next_node
+        end
+
+        def parent(node)
+          node.parent
+        end
+      end
+    end
+  end
+end