** SLOT-UNBOUND now correctly initalizes the CELL-ERROR-NAME slot
of the UNBOUND-SLOT condition to the name of the slot.
** (SETF (AREF bv 0) ...) did not work for bit vectors.
+ ** SLOT-UNBOUND and SLOT-MISSING now have their return values
+ treated by SLOT-BOUNDP, SLOT-VALUE, (SETF SLOT-VALUE) and
+ SLOT-MAKUNBOUND in the specified fashion.
planned incompatible changes in 0.8.x:
* (not done yet, but planned:) When the profiling interface settles