anchor.diff:  (defun last-byte-of-spec (spec)
     "Returns the last byte in the command vector occupied by spec."
     (case (type-of-spec spec)
  -    ('uword (+ 1 (second spec)))
  +    (uword (+ 1 (second spec)))
  +    (ulong (+ 3 (second spec)))
       (t (car (last spec)))))
       
   (defun command-length (command-spec)
  
positive.code: 		 turn-ratio (ubyte 6) ;; needs to be subyte, so this will fail with negative numebrs.
  		 run-state (ubyte 7)
  		 tacho-limit (ulong 8))
  (def-reply-package #x04)		 
  
  (def-nxt-command set-input-mode #x00 #x05
  
negative.code: ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;; Specification:
  ;;
  ;;     (ubyte position)  - byte = 8bits  (== byte)
  