Milestone Refactor and Cleanup

There's some crufty code that needs refactoring and cleanup, and some stuff that just plain doesn't work. Test coverage is poor, and the framework's support for testing is somewhat lackluster. The documentation and the tutorial are also radically out of date and inaccurate.

Tasks this milestone:

• Go over the docs and rewrite the stuff that's no longer accurate.
• Start adding to the tutorial
• Expand the RDoc class documentation
• Make the Arrow::AppletTestCase and Arrow::TestCase classes more useful
• Fix and finish the render template directive, and add any other ones that are small enough not to require any major changes to the code.