0.8.18.21:

0.8.18.21:
	Merge Robert J. Macomber's octets3.lisp (sbcl-devel 2005-01-06)
	patch.
	... use WITH-ARRAY-DATA for bounds checking and simple-array
		extraction;
	... implement ASCII external format (and MALFORMED-ASCII
		condition);
	... don't need CODE-RANGE type, we can use CHAR-CODE;
	... make it compile in #!-SB-UNICODE;
	... one or two other frobs.  I don't think this is in its final
		form even now, but it's good enough, and...
	Implement SB-MD5:MD5SUM-STRING, calling STRING-TO-OCTETS
	... adjust md5-tests.lisp to use it;
	... tests now pass.  Hooray.