shared.  The default is to save references to the integers in
	the range -1..99.  The lower limit can be set by defining
	NSMALLNEGINTS (absolute value of smallest integer to be saved)
	and NSMALLPOSINTS (1 more than the largest integer to be
	saved).
tupleobject.c: Save a reference to the empty tuple to be returned
	whenever a tuple of size 0 is requested.  Tuples of size 1
	upto, but not including, MAXSAVESIZE (default 20) are put in
	free lists when deallocated.  When MAXSAVESIZE equals 1, only
	share references to the empty tuple, when MAXSAVESIZE equals
	0, don't include the code at all and revert to the old
	behavior.
object.c: Print some more statistics when COUNT_ALLOCS is defined.