- nil_method now returns 0, not receiver.
- Metaclasses actually get their dtables installed with the new ABI. For some reason this wasn't being done, so class messages didn't work with the new ABI. Now they do and (at least some) nontrivial programs work.
- Undid commenting out of the code setting the fast ivar access pointers. I can't remember why this was commented out, but it seems not to break anything. I have an LLVM pass that makes compiled code access these pointers, but it's not committed yet.
