Add libxml to faster XML output generation

Gemfile

@@ -3,6 +3,7 @@ source "http://rubygems.org"
 gemspec
 
 gem 'yajl-ruby'
+gem 'libxml-ruby'
 
 group :test do
   gem 'rspec-mocks'

test/test_helper.rb

@@ -23,6 +23,8 @@ end
 
 require 'rabl-rails'
 
+ActiveSupport::XmlMini.backend = 'LibXML'
+
 module ActiveSupport
   class TestCase
     RSpec::Mocks::setup(self)