Instead of only checking the class_name(), we now generate an is_foo()
virtual in the wrapper generator. (It's currently something we override
on Bindings::Wrapper, which is not really scalable.)
Longer term we'll need to think up something smarter for verifying that
one wrapper "is" another type of wrapper.
This patch introduces a hackish but functional IDL parser and uses it
to generate the JS bindings for Node and Document.
We'll see how far this simple parser takes us. The important thing
right now is generating code, not being a perfect IDL parser. :^)
