Performance
My REXML::Element.to_ncr (and REXML::Element.to_utf8) is horribly slow. For long documents, it proves more efficient to serialize to a string, apply String.to_ncr (or String.to_utf8) and then Sanitize the string.

lib/chunks/engines.rb

lib/sanitize.rb

test/functional/wiki_controller_test.rb

test/unit/page_renderer_test.rb

test/unit/sanitize_test.rb