standardizing copyright/license notice delimiters in MIT source files.

[Greg Hudson]

Here's a proposal for updating the coding standards based on conference
call discussion:

* Each applicable copyright and license statement should appear in its
own block comment (not combined with the filename or file description).

* Copyright and license statements should appear before the first
non-blank non-comment line of the file.  (So, no more putting copyright
statements in the middle of files if they only apply to part of the
file.)

* Copyright and license block comments should begin with the word
"Copyright" or "License".

We had a brief discussion of whether it's useful to identify the
filename in the top comments, with one of us saying that it's sometimes
useful.  Assuming we keep that, prototype.c might look like:

/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* prototype/prototype.c */
/*
 * Copyright (C) 2010 by the Massachusetts Institute of Technology.
 * All rights reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

/*
 * <<< Description >>>
 */