Magic DSL

Nahi,  This is an insane amount of change from the original API (although the original API still works fine).  It depends on much magic and still needs quite a bit of work.  However, look at samples/line_chart.rb and samples/analog_clock.rb.  I think they look pretty nice.

The main issue now is generating scenes.  Since scene graphs nodes need to before creating the scene I think I can use a builder?  The layout_scene method on Stage is more of a hack than a final solution.  layout_scene is not quite right because I cannot easily attach listeners to the scene from within layout_scene.  I will figure out a solution to this soon though.