[R6RS] Core/lib split

[dyb at cs.indiana.edu]

BTW, if we do leave memq, etc., in the list library only, we should
consider rewriting or flushing the following 'or' example:

(or (memq 'b '(a b c)) 
    (/ 3 0))                    \ev  (b c)%

and also the following 'cond' example:

(cond ((assv 'b '((a 1) (b 2))) => cadr)
      (else \schfalse{}))         \ev  2%

both currently in base.tex.

Kent