(This file could stand some reorganization -- it's hard to tell the
open items apart from those that are done or nearly done.)
Do binary operators properly. nb_add should try to call self.__add__
and other.__radd__. I think I'll exclude base types that define any
-binary operator without setting the CHECKTYPES flag.
+binary operator without setting the CHECKTYPES flag. *** This is
+done, AFAICT. Even supports __truediv__ and __floordiv__. ***
Fix comparisons. There's some nasty stuff here: when two types are
not the same, and they're not instances, the fallback code doesn't