REXML is dead. Long live Nokogiri.

Modify Maruku to use Nokogiri instead of REXML.
Produces a 3-fold speedup in the #to_html method.

vendor/plugins/maruku/spec/block_spec.rb

@@ -0,0 +1,52 @@
+#!/usr/bin/env ruby -w
+# encoding: UTF-8
+Encoding.default_external=('UTF-8') if ''.respond_to?(:force_encoding)
+require File.dirname(__FILE__) + "/spec_helper"
+
+METHODS = [:to_html, :to_latex, :to_md, :to_s]
+
+describe "A Maruku document" do
+  before(:all) do
+    @old_stderr = $stderr
+    $stderr = StringIO.new
+  end
+
+  after(:all) do
+    $stderr = @old_stderr
+  end
+
+  Dir[File.dirname(__FILE__) + "/block_docs/**/*.md"].each do |md|
+    describe " for the #{md} file" do
+      input = File.read(md).split(/\n\*{3}[^*\n]+\*{3}\n/m)
+      input = ["Write a comment here", "{}", input.first] if input.size == 1
+      comment = input.shift
+      params = eval(input.shift)
+      markdown = input.shift
+      ast = input.shift
+
+      before(:each) do
+        pending if md =~ Regexp.new("^" + Regexp.quote(File.dirname(__FILE__) + "/block_docs/red_tests"))
+
+        $already_warned_itex2mml = false
+        @doc = Maruku.new(markdown, params)
+        @expected = METHODS.zip(input).inject({}) {|h, (k, v)| h[k] = v ? v.strip : '' ; h}
+      end
+
+      it "should read in the output of #inspect as the same document" do
+        Maruku.new.instance_eval(@doc.inspect).should == @doc
+      end
+
+      it "should read in the given AST as the same document" do
+        Maruku.new.instance_eval(ast).should == @doc
+      end
+
+      METHODS.each do |m|
+        it "should have the expected ##{m} output" do
+          res = @doc.send(m).strip
+          pending "install itex2mml" if m == :to_html && $already_warned_itex2mml
+          res.should == @expected[m]
+        end
+      end
+    end
+  end
+end