Fixed argv so that (argv 0) works.

scsh/scsh.scm

@@ -622,7 +622,7 @@
       (arg* arglist n)))
 
 (define (argv n . maybe-default)
-  (apply arg (cdr %command-line) n maybe-default))
+  (apply arg %command-line (+ n 1) maybe-default))
 
 (define (command-line) (append %command-line '()))