compute-coll-string can (and does) overshoot the collector data array

[reanz59]

Replacement code guards limit of from vector:

(defun compute-coll-string (coll) (declare (optimize (speed 3) (safety 1))) ;; return the string that's in the collection (let ((from (collector-data coll))) (subseq from 0 (min (collector-next coll) (array-dimension from 0)))))