Lua was happily compiling nil chunks and making them return empty
strings, which was not a good error experience in situations where
your file couldn't be loaded properly. Now we return nil plus an
error message, which matches LOVE and other Lua conventions.
- Ref struct only stores refcount now and is more general.
- Proxy stores a hash of its type name instead of an enum.
- Variants store additional information instead of using a vtable.
- Remove the concept of superclasses from the API.
- Clean up some miscellaneous includes.