Fixes and Enhancements from Demo/Updated Final Demo

-Fixed undefined and null vars issues in a few places causing errors in
IE and FF - JSO.Client.Model.Object, JSO.Client.Timer
-Moved GRAP-specific movement attributes from Actor to Object model so
they are available more generally.  I had them in the actor model only
for performance reasons - not functionality.
-Beginning to add Layer model.  This isn't complete.
-Stretched Box2D garbage collection out.  It was the source of the wavy
performance in IE.
-Still trying to fix that stupid problem of resources showing when the
game is loading.  It's not as simple as it might seem - I think it's
related to KineticJS.
-Added listen attribute on Game model and Event model.  This was part of
original spec.  I just finally got to it (because I had to make the
player die for the demo).
-Updates to NoCodeFinal Demo