Using the fresh egg

Implement our own sha1sum:
   (use utils)
   ; This makes the sha1 egg procedures available
   (use simple-sha1)
   (display (string->sha1sum (read-all))
   (newline)

SHA-1 hashsum of "hello world":
   $ csc sha1.scm
   $ echo -n "hello world" | ./sha1
   2aae6c35c94fcfb415dbe95f408b9ce91ee846ed