This fixes the upostop-- test by auto-casting implicit constants to
unsigned (and it gives a warning for signed-unsigned comparisons
otherwise). The generated code isn't quite the best, but the fix for
that is next.
Also clean up the resulting mess, though not properly. There are a few
bogus warnings, and the legit ones could do with a review.
#if 0 out the "normal" implementation, so that it doesn't hurt. When it
becomes possible to have the private Array methods separate, remove them
from the main file and remove the #if 0 block from Array+Private.r.
This version is a bit more useful, and we should be able to get rid of the
Stack class. Also, the Ruamoko parts of the autorelease system should be
almost ready now.
