Added AccessToken
Converted code to use AccessToken.
Changed block body ToMethod and ToConstructor to add the this type to the access token.
Added permission checks. Currently there is no way to expose the create object method.
Made fields handle permissions and work better when a subclass uses the same field name.
Added ability to define static methods from within the scope of the class instance.
Added ability to define assignment methods.
Added missing types to the error handler.