0.9.1.15:

0.9.1.15:
	Improve modular arithmetic by:
	* Making bounds of (unsigned) modular function type derivation
	  more precise;
	* Being less pessimistic when deriving bounds for LOGAND in
	  the case when its arguments are known to be bounded and
	  unsigned.  As a bonus, LOGIOR type derivation in the same
	  case is now more precise as well.

	The upshot of all this is that a function like:

	(defun foo (x y)
	  (declare (type (integer 0 3) x y))
	  (mod (- (+ x 4) y) 4))

	now uses only fixnum arithmetic.