5/6/69 22:16  JONL

PDL OVERFLOWS AND FREE-STORAGE EXHAUSTION
  ARE NOW ERRSETABLE AND BAKGAGABLE.
SUBLIS WORKS WELL, AS PER PAGE 12. OF THE 
  LISP 1.5 PROGRAMMERS MANUAL.  IF THE
  FIRST ARGUMENT HAS MULTIPLE ENTRIES FOR THE
  SAME ATOM, THE ENTRY CLOSEST TO THE HEAD OF
  THE LIST WILL BE USED IN THE SUBSTITUTION.
  E.G., (SUBLIS (QUOTE ((A.B)(C.(D E))(A.F)))
		(QUOTE (X A Y C Z)))
  EVALS TO (X B Y (D E) Z).