Blocks, functions, and methods now have the same code for handling
their bodies.
This means that single-line methods work like single-line functions:
they return the result of their expression.
They are compiled as local variables defined in an implicit
scope surrounding the class. This has the right semantics and,
better, means that there's no VM support needed for them.
They're purely syntax sugar.
They are now invoked like "new Foo".
Also, superclass constructors are now much less semantically
and syntactically weird. Since the instance is created before
any constructor is called, there's no point in time where the
instance isn't there.
